Rex Heuermann Studied the FBI's Playbook. Now They Want a Word.

What the Behavioral Analysis Unit May Be Looking and What They're Likely to Get

In the summer of 2009, a man used Melissa Barthelemy’s phone to call her teenage sister. He called more than once, over a few weeks. Melissa was already dead. He knew that, because he was the one who had killed her, and he told the girl on the line what he had done to her sister. The calls came from midtown Manhattan, a few blocks from the office where Rex Heuermann ran his architecture firm. A former FBI profiler said he made them for one reason. To hear the fear.

24-year-old Melissa Barthelemy

For fourteen more years, nobody connected those calls to the tall architect who commuted from Massapequa Park. He counted on that.

In April, Heuermann pleaded guilty to murdering seven women, admitted killing an eighth, and will die in prison. He did not give that up easily. For nearly three years, his lawyers fought to keep the case from ever reaching a jury, moving to throw out the search warrants, the DNA off a discarded pizza crust, the rootless-hair testing that tied him to the bodies. When the judge let that DNA in, the defense’s own attorney called the ruling monumental. The plea followed. It came with a condition. He has to sit down with the FBI’s Behavioral Analysis Unit, the profilers most people know from television, and answer their questions.

The obvious question is why. I’ve sat across from a lot of men like him, and why gets you almost nowhere. Ask a man why, and he hands you the story he has already told himself, smoothed down and easy to live with.

First, though, the women. Sandra Costilla was the first victim, murdered in 1993. She had come to New York from Trinidad and Tobago. Karen Vergata disappeared in 1996, and her case went unsolved for nearly thirty years. Maureen Brainard-Barnes had a sister, Melissa Cann, who spent nineteen years searching and waiting, always talking about how her sister was so much more than what happened to her.

Then Megan Waterman, Melissa Barthelemy, Amber Costello, Jessica Taylor, and Valerie Mack. Eight women. Most were doing sex work, and he believed that, when they went missing, no one would rush to report it. Heuermann counted on that, too.

I have spent more than thirty years interviewing violent offenders, and the first thing you learn is that, when the stakes are high, the man across the table almost always lies. You don’t sit down hoping he’ll be honest. You sit down knowing the case as well as you can, and you watch for where his story pulls away from the evidence. A straight answer tells you less than the things he skips over or changes. They show you what he can’t stand to admit, what he’s protecting, and how he saw the people he hurt.

In addition to relying on my own forensic experience, I watched interviews FBI profilers had done with other serial killers, men like Ed Kemper, John Wayne Gacy, and Joel Rifkin: different killers, different decades, different interviewers. I found seven. I then compared them with what we know about Heuermann and the evidence that led to his arrest. How might the specifics of his case influence the interview? What is likely to stay the same?

Understanding Access

A profiler wants to know how a man got a stranger close enough to kill his victim; it can tell you more about him than the killing itself. The killing looks much the same from one offender to the next. The approach doesn’t. It holds his planning, his nerve, the face he wears in public, the world he walks through without anyone looking twice. Practice leaves a mark.

Most will talk about it, too. Access is where a man feels skilled instead of ashamed, so he walks you through the approach in detail, almost proud of it. And you can check what he says against what you know. We know roughly how Heuermann found his. In the early years he went looking in person, in the sex-work areas of Brooklyn and Manhattan; his first victim, Sandra Costilla, was a woman he arranged to meet in 1993, years before Craigslist carried that kind of ad. When the trade moved online in the 2000s, he moved with it, and six of the eight advertised on Craigslist or Backpage.

What we don’t know is how he made a stranger comfortable enough to come to his house. That is the problem every one of these men has to solve, and each solves it in his own way. Ed Kemper was six feet nine and built like a wall, the last man a young woman would want to be alone with, so he taught himself to glance at his watch when he offered a girl a ride. A man checking the time is a man with somewhere to be, harmless, in a hurry, no threat to anyone. Heuermann did it by going slowly. Prosecutors believe he met the women at least once before he brought them home, long enough to turn from a stranger into a familiar face.

When Douglas got Joseph Kondro talking about how he lured his victims, the answer was trust. Kondro killed the young daughters of families he was close to, children who had no reason to fear a parent’s friend. His way in ran through that trust, which teaches an investigator to look first at the people already close. Safarik walked Joel Rifkin through how he found the women he killed, and the method was a thread to pull. Rifkin worked one kind of transaction, in one kind of place, over and over, and a man who finds his victims the same way every time leaves a trail you can match to cases no one tied to him.

Most of why the unit does these interviews comes down to that. The way a man gets access works like a fingerprint. Held up against open cases, it can link killings nobody connected, turn up victims he was never charged with, and show investigators what the next man like him will look like before he is caught.

His access leaves real ground to cover. It was a paid meeting, arranged in advance on a burner phone, with women the world was slow to miss. The BAU will want the whole of it: how he found them, how he screened them, what he said, how he chose. A method this clean is rarely used, only eight times, so his answer could open the door to victims no one has counted. It would also explain the thing that still seems impossible, how a married father with a Manhattan practice did this for decades while no one close to him noticed. Kemper’s watch again, the harmless man, running much longer.

He Took Notes on the Book About Catching Him

Nobody is good at staying hidden on the first try. The early crimes come out clumsy, the later ones clean, and how careful a man got tells you roughly how long he had been at it. So after access, a profiler turns to how he kept from getting caught. A man who learned to disappear that well, practiced on someone, which is strong evidence that he killed more often than anyone charged him with.

It also tells you which kind of offender you have, the careful one or the one nobody ever looked for. Those are two different men, and they call for different investigations. A man will usually walk you through his precautions in detail, and somewhere in that detail is where he got his ideas.

Donald Harvey, the hospital orderly, built concealment into the crime before he ever acted. He chose patients already expected to die, so no one questioned a death, and he varied his methods and watched his dosages to leave nothing behind. When Douglas drew him out, Harvey knew a startling amount of forensic detail, which marks came from which method, how cyanide reads differently from one body to the next, much of it picked up from a funeral-director lover. A shortcut he took in a hurry caught him in the end. Ed Kemper stayed hidden by getting close to the people hunting him. He befriended local police, drank where they drank, listened to updates on the case, and watched television cop shows to learn what investigators looked for. Joel Rifkin modeled himself on how the Green River Killer operated and stayed uncaught.

When an offender tells you where he learned to stay hidden, he hands the BAU a map: the books and cases he drew on, the mistakes he fixed, the year his method came together. Lined up with the known crimes, that map shows where the uncharged ones probably fall, and it fills in the blind spots that let him keep working. It also tells you he knew what he was doing and worked to get away with it, which closes off any later story about losing control.

Heuermann brings his own evidence into that room. On a hard drive in his basement, investigators found a deleted Word file that the prosecutors call the planning document, written around 2000 and edited into 2002. He sorted it under headings: problems, supplies, targets, dump sites, body prep, with DNA listed as the first problem to solve. In a section he labeled “Things to Remember,” he kept notes like these:

Use push pins to hang drop clothes from ceiling - not tape.

Use heavy rope for neck - light rope broke under stress of being tightend.

It was all business. He tried something, it didn’t work, and he wrote down the fix. The task force read his notes about doing things differently “next time” as a sign that he already had experience to learn from.

Some of the notes were copied. Prosecutors say parts were lifted word for word, with page numbers, from John Douglas’s Mindhunter, written by the man whose old unit will now question him. He copied out Douglas’s split between an “Originanized” and a “disoriginanized” offender, misspellings and all, the pages marked up like a student outlining a chapter. He read how the FBI catches serial killers and took notes on how not to be caught.

Rifkin took his lessons from a killer who got caught. Heuermann took his from the people who do the catching. The BAU will walk him through that file the way you walk a student through his own homework, page by page: which lessons he kept, which he dropped, what he added on his own that no book taught him, and when he wrote each part, against which killing. A file begun around 2000, worked on for years, describing methods the prosecutors say match how the women died, is hard to square with a man who killed exactly eight times and then happened to stop.

What Stops Them

Could you have stopped on your own? A profiler asks each of these men some version of that question because the answer is telling. There is a difference between a man who kills because something in him keeps demanding it and a man who kills when the chance falls in his lap. Which one you have tells you how dangerous he is, whether he was getting worse, and whether anything short of a cell was going to stop him.

Everyone who got the question gave the same answer. O’Toole asked Rhodes whether he’d have kept going, and he said there would have been more victims until he was caught. Safarik asked Rifkin, who said believing he could stop was one of the lies you tell yourself. Douglas asked Joseph Kondro, and Kondro said killing had become second nature, that he just kept going. By their own telling, the only brake was an arrest.

Two famous cases complicate that. Dennis Rader killed Dolores Davis in January 1991 and then was silent for thirteen years. Joseph DeAngelo stopped after he murdered Janelle Cruz in 1986 and stayed free for more than thirty years. So some men do stop killing. But the killing stopping and the urge leaving are two different things. Rader couldn’t let it alone. He started taunting the police again in 2004, and his own letters gave him up. DeAngelo went cold for real, raised three daughters, and stayed free until a DNA match undid him decades later.

There’s another use for the question. These men get better with practice. The early crimes are smaller and clumsier, the violence sharper later on. That points an investigator back toward the rougher early crimes nobody ever pinned on him, and, while he’s still loose, it shows the direction he was traveling.

Heuermann has a long silence of his own. The known killings run from 1993 to around 2010, and then, as far as anyone has shown, they stop, more than a decade before his arrest. His own behavior puts that silence closer to Rader’s than to DeAngelo’s. Prosecutors say that right up to 2023, he was still using burner phones to contact sex workers hundreds of times, under aliases, and running thousands of searches for violent pornography, along with more than a hundred about the Gilgo case itself.

He never lost the hunger, and he barely hid it. Tierney said they moved when they did because Heuermann was still contacting sex workers and possibly still dangerous, and because they feared details of the investigation would leak. He wasn’t caught mid-killing; he was watched and then taken in.

And the searches were not idle. For men like him, the killing begins as fantasy, years before the first body, and that fantasy is the engine under all of it, the thing that keeps running between killings. It has to be fed. A man who runs thousands of violent searches and reads his own case over and over is feeding it, keeping it alive on paper and on the screen when there is no one left to act it out on.

So the BAU will press him on what those quiet years held. Either he stopped the killing and nothing else, or there are killings no one has tied to him. The record already shows he never lost the urge.

What He Got Out of It

Some of what a killer does is purely practical, the work of getting it done and not getting caught. The parts that served no practical purpose, the things he had no need to do, are the ones that show what he was after. Call it the payoff. Once you have it, the rest of the case falls into place: who he chose, and what he needed from them.

In my experience, the payoff is almost always power and control, and it almost always arrives in costume. The mercy killer. The man who was wronged. The “rough sex” that went too far. The one who lost control. A good interviewer lets him wear it a while, then keeps asking the questions until what’s under the costume shows. He did it because it made him feel powerful, and nothing else in his life did.

The seven interviews BAU staff reached the same place from different directions. Kemper could lay it all out in detail, the fantasy he’d built since boyhood, what it meant to hold complete control over another person, why he kept parts of them. Rhodes, pressed by O’Toole, kept circling power and the victim’s fear even as he denied that her fear was the point. Rifkin described strangling women in cool, technical language, but he was describing the slow, total control of someone’s last minutes. He kept their belongings so he could return to them later.

A profiler chases the payoff because it explains the parts of a crime with no practical reason. Those parts are the signature: how he bound them, what he did beyond what killing required, what he took, and whether he came back. The signature holds steady even when his methods change, which is why it links one case to the next and marks them as the work of one man.

Heuermann’s payoff is already visible, but the BAU will want it from him. He bound the bodies, wrapped them, and laid them along the same stretch of beach. None of that is required to get rid of a body. Prosecutors say his planning notes and his searches run heavily to torture, and that the document talks about keeping a victim for “play time.” The taunting calls were the same need still running after the woman was dead, control he could hold over her family once he could no longer hold it over her. His payoff was power over another person, total, drawn out as long as he could make it last.

The Line He Won’t Cross

Almost every man I have interviewed had a line of self-disclosure he would not cross. Maybe he’d give up the killing but deny the sexual assault. Or insists he thought the victim was older than she was, despite overwhelming evidence to the contrary. The story becomes vague. He turns it into something he can live with, or he says he doesn’t remember. He guards that one spot because a man protects what he can’t stand to be.

A profiler watches for that on purpose. What a man won’t own tells you what the crime meant to him and how he needs to see himself, which are usually the same thing. So when he clams up, a good interviewer doesn’t ease off. He leans in.

It looks different from one man to the next. Reginald McFadden gave up the killing but recast the sexual assault as something else, even though the autopsy contradicted him. John Wayne Gacy guarded his image as an upstanding citizen and a wronged, respectable contractor, and he bent every fact to protect that portrait. Rhodes admitted the power but not that the victim’s fear was part of the pleasure, until O’Toole walked him into the holes in his own story. Each time, what the man refused to say told the interviewer more than everything he gave up.

When a man reframes the worst part, a good interviewer doesn’t argue. There’s no point. He holds the story up to the evidence and waits for the seam to show. Safarik didn’t have to talk McFadden out of anything. He had the autopsy, and it told him the truth.

Heuermann has shown the world a planner, a problem-solver, a man who keeps notes like a contractor, and that is most likely the voice he brings to the room: supplies, dump sites, methods, the cleanup. If he runs true to the men before him, and to the document he left, the place he goes quiet is the place McFadden did, on what he did to the women and what it gave him. The sexual core, the cruelty the document only gestures at, the satisfaction the whole thing was built on, that is what the logistics are there to cover.

And the BAU has what Safarik had. Heuermann left them a record himself, the document, the searches, the calls, the bodies, and it shows what his careful account leaves out. The missing pieces matter more with him than usual, because he wrote the procedure down in detail and kept his own pleasure almost entirely off the page. What he leaves out of the room is what he left out of the document: himself, enjoying it.

Sorry He Got Caught

Near the end of one of these interviews, a profiler asks the simplest question. Any regrets? A man who has killed more than once tends to carry two regrets. There’s the one he is supposed to feel, for the people he killed. And there’s the one that bothers him, the mistake that got him caught, usually a method that failed or a body that turned up where it shouldn’t have.

Which one he reaches for tells you how dangerous he still is. The operational regret, the second-guessing about method, is often more honest than the rest of what he says, because he forgets to dress it up. A man who tells you he should have hidden her better has just told you how he was thinking.

Both kinds show up in the interviews. Douglas asked Donald Harvey what he would have done differently, and Harvey said he wouldn’t have used the cyanide and would have cleaned the feeding tube out better, the slip that finally exposed him. He was sorry he got caught. The dozens he killed never came up.

Douglas asked Joseph Kondro the same question, and Kondro opened with the performance: he should have gotten the death penalty; his victims got no justice. Douglas didn’t buy it and pushed, asking what he would have done differently. Kondro said he’d have taken the girl somewhere her body would never be found. Douglas told him that sounded closer to the truth, and it was.

Now and then you get something else. Kemper came nearer than the rest, talking about people who were dead who would otherwise be home with their families, and about not turning himself in sooner. It’s rare enough to stand out, and real enough, when it comes, that you tend to know. Especially when you’ve turned yourself in.

Heuermann has given us some clues. The lessons-learned notes in his planning document are operational regret, mistakes written down with better solutions going forward. The rope that broke. The hit that wasn’t hard enough. Each one is him being sorry that something didn’t work, fixing it for next time. Not one of them is about a woman.

So when the BAU asks him what he regrets, they know what he felt in private. I’d be surprised if he pretended to feel sorry for actual murders; in fact, I doubt he’ll ever show many emotions at all. But I’d bet he feels regret for the things that failed him, the pizza crust that held his DNA, the burner phones, the calls that put him near his office, the rope. I bet he’s sorry he was caught. To him, the eight women will be the part that worked.

Rex Heuermann’s latest mug shot

Stopping the Next One

Catching the next serial killer is a worthy goal. So is preventing the next troubled kid from becoming one. As a forensic psychologist and forensic investigator, I hope we mine for both. I have a million questions.

When did he first think about hurting someone, and who was it? How old was he? How did he think violence might help? What specific thoughts did he have? What was he feeling? What was going on in his life at the time? How often did he think about it? What would have helped him deal with those thoughts? Who knew about them? How did he hide them?

What were his first sexual experiences? When did violence and sex become intertwined in his fantasies? What purpose did they serve? How often did he have them? When and how did he discover pornography, and how did his tastes in it evolve? Who else knew about it?

When did fantasizing turn into planning? What shifted? How long did you fantasize before you started planning? How long did you plan before you acted? What story did you tell yourself along the way? Who could have stopped you or changed your mind? A man can answer those questions. They lay out the path he walked from a thought to a body. Once there’s a body, it is already too late.

What happened in the gaps between murders? Were there stretches when he thought about killing but didn’t? What stopped him? How did he go to work, raise his kids, get through a Sunday, and deal with his fantasies in between? Learn what kept a man off the path for a year, or five, and you’ve learned something about where someone could have stepped in.

It can be done. Douglas walked Kondro back to seventh grade, where the fantasies started, and drew out the first time he tried to act on one and stopped, because the girl cried and he lost his nerve. There are many steps along the serial killing path where someone either almost got off or could have. Important clues are how it began, and an early moment when it almost stopped.

Heuermann built the planning document around 2000 and edited it for about two more years, marking the point at which the thinking became a written plan. But Sandra Costilla died in 1993, seven years before he opened that file, so it all started well before the document did.

The rest is what I’d want from him: when the thought first came, who, if anyone, caught a glimpse of it, and what he did across the long stretches he wasn’t killing. Then ask what the killing gave him, and what else in his life ever came close to it.

If I could get him to name that, I’d understand the quiet years, because a man doesn’t go a decade without the urge unless something is feeding it. Some of that is already on the record. The contacting and the searching never stopped, and after he killed Melissa Barthelemy, he used her phone to call her teenage sister and listened to the voicemails of women he had killed. Control like that outlasts the murder. It tells you the killing was never the whole story, and that he kept feeding it long after.

Two more I’d ask, both about who he thinks he is. Which killer do you identify with? He studied Douglas, so he had models, and the name he reached for would tell you whose story he saw himself in. And who do you most admire, as a person? The answer would cut against the architect, the husband, the churchgoer he showed the world.

None of this catches him. It points to a different problem: how a man gets from the first thought to the first body. But none of it, the FBI’s questions or mine, gets answered unless he decides to talk.

“Don’t Let Them Gloat”

Heuermann already pleaded to the maximum, three life sentences and more, so there is nothing left to hold over him. A former federal prosecutor said it plainly: if he sits with the agents and lies, or never shows up at all, his sentence does not change. The district attorney has called these clinical interviews, not investigative ones, an academic exercise. No one has promised they will close a single case.

So whether the agents get anything real depends on what Heuermann decides, because the deal gives them no way to make him tell the truth. With no leverage left, the only lever is rapport, the slow work of building a connection, since pressure has nothing to push against. And in a man like this, two things pull against each other.

One is the pull to compete. Unlike some serial killers, Heuermann has not sought out public attention. Rader mailed the police his poems and named himself BTK; Heuermann hid, and the hiding was the point, the life kept from everyone around him.

But what might draw him out in that interview room is the contest. He studied the people hunting him, copied their book into his own notes, and stayed ahead of them for years. Now he is across the table from that same unit, and the pull is to show them he was the better mind, that they got him on a stray hair and a thrown-out pizza crust and not on anything they out-thought. To flex, for the only people in the world equipped to measure what he pulled off.

He also has every reason to keep quiet or lie, and none of them are strategic. There are no chips left to trade and nothing to gain by talking. If he holds back, it is not because the secret buys him anything. It is because the secret is his, and has been his alone for thirty years, hidden from his wife, his kids, everyone who thought they knew him. Handing it to the FBI means giving away the one thing he never had to share.

He has already gotten advice along these lines, from a man who would know. Soon after his arrest, a letter reached him from an Oregon prison cell. It was from Keith Jesperson, the long-haul trucker who killed at least eight women in the early 1990s and signed his taunts to the press with a smiley face, which is how he became the Happy Face Killer.

Jesperson collects cases like this one and coaches other accused killers, and he wrote to Heuermann the way an older hand instructs a new hire. His advice, in a letter he would later make public, was to settle rather than fight, so the prosecutors would never get to gloat over their evidence. Heuermann thanked him for it and wrote back.

I don’t believe Jesperson had anything to do with Heuermann’s decision to plead. The reason was the DNA the judge let in, and all the motions the defense team lost. But the instinct behind the advice is the one Heuermann carries into the interview. Give them nothing to gloat over.

Unfortunately, Jesperson does not follow his own advice. He talks without stopping. He confesses to old cases, hands police closed files, writes to anyone who will print him. We know what he told Heuermann only because he gave the letters to a podcaster who interviews killers. The man counseling silence is the loudest killer in the system because talking is, in his mind, how he stays someone.

That is the conflict Heuermann will have to resolve: the pull to prove he won, set against the pull to keep his inner world hidden. What the agents get depends on which one wins.

What They’ll Actually Get

This is not a confession waiting to happen. Based on previous interviews with serial killers and Heuermann’s own document, these sessions are likely to produce the method in full and almost nothing about the man behind it. Even so, the method is worth having, and so is the count, which is what the families are still waiting on.

That victim count is the part people most want him to give up. Suffolk County’s cold case unit is still working on unidentified-remains cases going back decades. Since his arrest, investigators have looked at him for killings in other states he had ties to, New Jersey, Nevada, and South Carolina. If one of those turns out to be his, the case stops being Long Island’s alone.

None of it depends on his cooperation, though. His method ties cases together with or without his help, not as cleanly as a fingerprint but closely enough to matter, and given a deal he can walk away from at no cost, the count is far more likely to come from the evidence than from anything he chooses to say.

And in the end, the interviews are for the women. Sandra Costilla and Karen Vergata waited years for anyone to say their killer’s name. Maureen Brainard-Barnes’s sister searched for nineteen of them. Melissa Barthelemy’s younger sister was a teenager when he used her dead sister’s phone to call her and make sure she was afraid.

Heuermann counted on all of his victims being forgettable, the kind of women no one comes looking for. He was wrong about getting caught. Whatever else comes out of that room, let it be the proof that he was wrong about the rest.

As always, thank you for reading this issue of The Mind Detective. If you’ve enjoyed it, please pass it along to a true crime friend. See you next week!

A note on sources

For this piece, I reviewed seven publicly available interviews conducted by former FBI behavioral analysts with convicted killers: John Douglas with Ed Kemper, Donald Harvey, and Joseph Kondro; Robert Ressler with John Wayne Gacy; Mary Ellen O’Toole with James “Dusty” Rhodes; and Mark Safarik with Joel Rifkin and Reginald McFadden. I treated them as qualitative material, not as a statistical sample, looking only for the questions the interviewers kept returning to. The rest draws on my own years interviewing violent offenders.

The Heuermann material comes from the April 2026 guilty plea and the Suffolk County District Attorney’s filings in the case, including the bail application that describes the planning document, the burner phone, and DNA evidence, as well as the taunting calls. The account of the three-year evidence fight, the Frye ruling on the rootless-hair DNA testing, and the terms of the FBI cooperation come from contemporaneous court reporting. The Keith Jesperson correspondence, including his advice to settle and Heuermann’s reply, comes from the letters Jesperson himself made public through a true-crime podcaster in 2023 and the reporting that followed. The comparison between Dennis Rader and Joseph DeAngelo is drawn from contemporaneous reporting on each.

The seven interviews are all on YouTube: Kemper / Douglas, “Kemper on Kemper”; Harvey and Kondro / Douglas, “Mindhunter” (2008); Gacy / Ressler (1992); Rhodes / O’Toole, “Profiling Evil”; Rifkin / Safarik, “Criminal Mindscape”; McFadden / Safarik, “Criminal Mindscape.”