Join Fox News for access to this content
Plus special access to select articles and other premium content with your account - free of charge.
By entering your email and pushing continue, you are agreeing to Fox News' Terms of Use and Privacy Policy, which includes our Notice of Financial Incentive.
Please enter a valid email address.
By entering your email and pushing continue, you are agreeing to Fox News' Terms of Use and Privacy Policy, which includes our Notice of Financial Incentive.

Prosecutors now say suspected serial killer Rex Heuermann kept meticulous notes on how to kill and get away with it as his alleged methodology changed over the course of nearly two decades and at least six murders he is accused of committing.

Graphic content warning

A deleted document investigators say they recovered from his computer shows he noted how many traffic cameras he would pass on his way to the dump sites, how to "prep" a victim's body for disposal and a reminder to use push-pins to hang a drop cloth, Dexter Morgan style, rather than tape.

Although investigators now say the suspected killer evolved over the years, many of the victims were discovered wrapped in some kind of material, whether it be a hunter's camouflage burlap or a surgical drape.

GILGO BEACH SERIAL KILLER SUSPECT ALLEGEDLY HAS MORE VICTIMS, HUNTING GROUNDS THAN POLICE FIRST IMAGINED

Rex Heuermann appears in court

Rex Heuermann, charged in the Gilgo Beach serial killings on Long Island, appears for a hearing at Suffolk County Court in Riverhead, N.Y., Thursday, June 6, 2024. Heuermann was charged Thursday in the deaths of two more, after prosecutors said they gathered new DNA evidence and found a computer document he had used to "blueprint" his crimes. (James Carbone/Newsday via AP, Pool)

Despite his alleged efforts to scrub away evidence of his own DNA and fingerprints, prosecutors have alleged that hairs found on multiple victims belonged to either Heuermann or members of his household.

His family has not been accused of assisting in any of the crimes – they were out of town during each murder, according to court documents.

Read Exhibit B, the HK2002-04 file:

In a statement released by her attorney, his estranged wife Asa Ellerup said she does not believe Heuermann is capable of committing the crimes and that she was unaware of his activities, if what prosecutors allege is true.

Asa Ellerup and daughter Victoria Heuermann departs the Suffolk County Courthouse

Rex Heuermann's estranged wife Asa Ellerup, center, and daughter Victoria Heuermann, left, depart the Suffolk County Courthouse in Riverhead, New York on Tuesday, Jan. 16, 2024. Ellerup filed for a divorce from her husband after police arrested him last year but has said through her attorneys that she doesn't think he is capable of the horrific crimes he is accused of. (Robert Miller for Fox News Digital)

"Today's Indictment further illustrates that, Asa Ellerup has no involvement in any of the alleged crimes that her estranged Husband, Rex Heuermann, has been charged with," said her lawyer, Bob Macedonio. "Ms. Ellerup married Rex Heuermann in 1996. She was not residing with Rex Heuermann in the Massapequa Park domicile in 1993, the year Ms. Costilla was murdered. Moreover, according to the Government, at the time of the death of Ms. Taylor, Ms. Ellerup was, once again, not in the jurisdiction."

Michael Brown arrives to court

Rex Heuermann's attorney Michael Brown, right, arrives to the courtroom in Riverhead, N.Y., Thursday, June 6, 2024. Heuermann, the New York architect accused of killing four women and leaving their bodies near Long Island's Gilgo Beach, has been accused in the deaths of two more women.  (AP Photo/Seth Wenig)

According to the filings, police have now received reports of Heuermann's old Chevy Avalanche from two witnesses in connection with two separate murders. They have decades of phone records and internet searches. They have his DNA.

REX HEUERMANN'S FAMILY KEPT GRUESOME PIECE OF EVIDENCE, SOURCE SAYS

Portraits of the Gilgo Four victims inset over a wide shot of the marsh behind Gilgo Beach where they were found

The "Gilgo Four" clockwise from top left: Maureen Brainard-Barnes, Melissa Barthelemy, Megan Waterman and Amber Costello. The background shows a wooden cross in the marsh next to Gilgo Beach, New York, where their remains were found in the brush just yards from Ocean Parkway. (Suffolk County Police Department/Mega for Fox News Digital)

And they have meticulous notes in a computer file called "HK2002-04," which Heuermann allegedly deleted from a computer – but not fully. Forensic investigators found it.

The file has lists of "problems," "supplies," dump sites and targets. It has checklists for "pre-prep," "prep" and "post event." There are notes including page numbers from FBI profiler John Douglas' groundbreaking book, Mindhunter. And the number of traffic cameras along two highways between Heuermann's home in Massapequa Park and the dump sites in Manorville and North Sea are listed.

Suffolk County District Attorney Ray Tierney speaks to reporters during a news conference

Suffolk County District Attorney Ray Tierney speaks to reporters during a news conference in Riverhead, N.Y., Thursday, June 6, 2024. Rex Heuermann, the New York architect accused of killing four women and leaving their bodies near Long Island's Gilgo Beach, has been accused in the deaths of two more women.  (AP Photo/Seth Wenig)

A section on "things to remember" notes that sound travels, killing without proper sleep "creats (sic) problem," and "hit harder." 

SUSPECTED SERIAL KILLER REX HEUERMANN'S HOME SEARCHED AGAIN

Closeup portrait Photos of Jessica Taylor and Valerie Mack.

Jessica Taylor, left, and Valerie Mack, right, were both murdered and dismembered. Suffolk County police discovered partial remains of each victim in both Manorville, N.Y., and along a stretch of Ocean Parkway near Gilgo Beach. Heuermann was charged with Taylor's murder Thursday, but in court documents, prosecutors suggested he may be suspected in Mack's case as well. (Suffolk County Police Department/Handout)

"Use push pins to hang drop clothes from ceiling – not tape," it reads. And light rope breaks too easily "under stress of being tightened" – use the heavy kind.

A section on "body prep," contains gruesome, step-by-step instructions for disposing of the victims, including "wash body inside and all cavities" and "remove trace evendice (sic) [finger prints/hair]." 

SIGN UP TO GET TRUE CRIME NEWSLETTER

An undated photo of Sandra Costilla

An undated photo of Sandra Costilla. Prosecutors announced that Rex Heuermann is charged with the alleged murder of Costilla, whose remains were found in November 1993, on Thursday, June 6, 2024.

If the allegations prove true, he failed.

"There are so many smoking guns this looks like a battlefield," said Joseph Giacalone, a retired NYPD sergeant and a cold case expert at John Jay College of Criminal justice. "The issue that it comes down to is the evidence in these cases now, as well as the Gilgo Four, in my opinion, is insurmountable."

GET REAL TIME UPDATES DIRECTLY ON THE TRUE CRIME HUB 

An evidence photo shows Rex Heuermann’s personal copy of

An evidence photo shows Rex Heuermann’s personal copy of "The Cases That Haunt Us," a book detailing several famous serial murder cases, in his home office. According to court documents, the book was discovered during authorities’ initial search warrant execution in July 2023. (Suffolk County District Attorney's Office)

He said he believes prosecutors may have already offered the suspect a plea deal in exchange for full information on the scope of the crimes.

"At this point, what is the defense going to be? Are you going to try to attack the new technology? Good luck with that. Are you going to try to attack hair [found] at the scene? And his wife’s hair? Good luck," he said.

"We don’t even know if there are any photos of this either," he added.

Suffolk County District Attorney Ray Tierney arrives to the courthouse

Suffolk County District Attorney Ray Tierney arrives at the courthouse in Riverhead, N.Y., Thursday, June 6, 2024. Rex Heuermann, the New York architect accused of killing four women and leaving their bodies near Long Island's Gilgo Beach, has been accused in the deaths of two more women.  (AP Photo/Seth Wenig)

In the document prosecutors allege they recovered from Heuermann's computer, one of the items listed under "supplies" was "photo film."

FOLLOW THE FOX TRUE CRIME TEAM ON X

Heuermann was arraigned on two new murder charges Thursday in the deaths of Jessica Taylor in July 2003 and Sandra Costilla in November 1993. They were both tortured and brutalized – with Costilla suffering 25 post-mortem stab wounds, according to prosecutors. Taylor was dismembered, with body parts dumped in two locations.

Shannan Gilbert missing woman Long Island

Police uncovered 11 sets of remains in the brush along Ocean Parkway after Shannan Gilbert vanished into the night after placing a panicked 911 call begging for help in 2010. Her remains were found near Oak Beach, New York on Dec. 13, 2011.  (The family of Shannan Gilbert)

John Kelly, a criminal profiler and the founder of STALK Inc., said serial killers typically evolve over time, especially if they are active for many years.

"When they start they start to experiment with different methods of killing until they find their method of choice," he told Fox News Digital. "The same with this guy's torture of choice, he experimented, until he found the one that gave him sexual excitement and satisfied his fantasy."

The Gilgo Four victims were all found under similar circumstances to one another. Dramatic differences in the Taylor and Costilla cases could lead investigators to investigate Heuermann in connection with a number of unsolved murders that didn't match the original methodology, he said.

Gloria Allred speaks to the media

Gloria Allred, attorney for the family of Jessica Taylor, speaks to the media alongside Elizabeth Baczkiel, mother of Taylor, after accused Long Island serial killer Rex Heuermann appeared in Suffolk County Court in Riverhead, New York on Thursday, June 6, 2024. Prosecutors charged Heuermann with the deaths of Taylor and Sandra Costilla on Thursday. (Michael Ruiz/Fox News Digital )

Police arrested the 59-year-old New York City architect last year in connection with three cold case murders and prosecutors secured an indictment for a fourth victim months later. He made a brief appearance in court Thursday in a suit and handcuffs, and is due back on July 30.

In July 2023, police arrested Heuermann outside his Manhattan office and spent nearly two weeks scouring through his home in Massapequa Park, about 20 minutes from where police found the bodies of Melissa Barthelemy, 24; Megan Waterman, 22; and Amber Costello, 27, in 2010.

Prosecutors later tacked on charges for the murder of Maureen Brainard-Barnes, 25, whose remains they found near the others.

The prime suspect in Costilla's death was previously another serial killer, former Manorville carpenter John Bittrolff, who is currently in prison for two other murders.

John Bittrolff listens to his attorney William Keahon during his arraignment on murder charges i

In this July 31, 2014 file photo, John Bittrolff listens to his attorney William Keahon during his arraignment on murder charges in Riverhead, N.Y. Suffolk County Assistant District Attorney Robert Biancavilla said Tuesday, Sept. 12, 2017 that Bittrolff, convicted of killing two prostitutes in the 1990s may be responsible for at least one of the 10 unsolved killings of people along a Long Island beach highway.   (James Carbone/Newsday via AP, Pool, File)

CLICK HERE TO GET THE FOX NEWS APP

Suffolk County District Attorney Ray Tierney, the lead prosecutor on the case, told reporters Thursday that investigators were still examining hundreds of electronic devices seized last year from Heuermann's home. 

Heuermann has pleaded not guilty in all six murders. His trial is expected to be further delayed as a result of the new indictment.

Cold case investigators in New York and at least three other states are looking into his potential connection to additional homicides.

"I think when all is said and done, we're gonna find out that Rex is one of the most prolific serial killers we've ever seen," Giacalone predicted. "This opens up dozens, if not scores of available victims for Rex from 1993 or even before, because it still puts him at the 31 years of age mark, which is still pretty old compared to some of the other killers we’ve seen. And we have that huge gap between 2011 and his arrest in 2023."