Accused Gilgo Beach serial killer Rex Heuermann kept a stomach-churning “planning document” mapping out his grisly slayings — which even included a chilling “Things to Remember” section and a morbid “Lessons Learned” section, officials revealed.
A computer “allocated space” file that Heuermann allegedly tried to delete laid out a gruesome road map of the vicious murders of six sex workers dating to 1993 — including the decapitation and mutilation of two victims newly tied to the hulking Long Island dad, Suffolk County prosecutors said Thursday.
In one disturbing notation, Heuermann allegedly indicated he planned to keep killing, prosecutors said.
“The GIlgo Homicide Task Force members believe these references to ‘next time’ indicate Heuermann’s prior experience and what changes to implement moving forward,” the DA’s filing said.
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The revelation came as the DA’s office slapped Heuermann with new charges in the 1993 slaying and mutilation of Sandra Costilla and decapitation and dismemberment of Jessica Taylor in 2003 — on top of the pending felony charges he already faced in the deaths of the women known as the “Gilgo Four.”
Who were the Gilgo Beach victims?
Suspected serial killer Rex Heuermann — a New York City architect and married dad of two — was arrested in connection with thelong-unsolved Gilgo Beach murders. The arrest is tied to the so-called “Gilgo Four,” women found wrapped in burlap within days of each other in late 2010.
The years-long investigation that led to the arrest revolved around thediscovery of more than 10 sets of human remainsalong Ocean Parkway near Gilgo Beach in Suffolk County between December 2010 and April 2011.
Most victims were petite female sex workers with green or hazel eyes. But there were also two exceptions: a 2-year-old girl and a young Asian man.
Melissa Barthelemy, 24
- Barthelemy was a sex worker who lived in the Unionport section of the Bronx and dreamed of one day opening her own beauty salon. She was last seen alive in her basem*nt apartment on Underhill Avenue on July 12, 2009. Heuermann was charged for Barthelemy’s murder in July 2023.
Maureen Brainard-Barnes, 25
- Brainard-Barnes was living in Norwich, Connecticut. She went missing after taking an Amtrak train from New London, Connecticut, to Grand Central Terminal in Manhattan on July 6, 2007. Her remains were found in December 2010. Heuermann was charged for Brainard-Barnes’ murder in January 2024.
Amber Lynn Costello, 27
- Costello, 27, was a sex worker and heroin addict who lived in West Babylon, New York, at a home with a woman and two men. She advertised on Craigslist and Backpage to support her and her roommates’ drug habits. Costello was found on December 13, 2010, after having been last seen leaving her home September 2, 2010. Heuermann was charged for Costello’s murder in July 2023.
Megan Waterman, 22
- Waterman, a 22-year-old mom of one, was last seen on June 6, 2010. She lived in Scarborough, Maine, and earned a living as an escort. She was last seen by her family boarding a New York-bound Concord Trailways bus in Maine. Her body was found on December 13, 2010, on the north side of Ocean Parkway, near Gilgo Beach. Heuermann was charged for Waterman’s murder in July 2023.
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Jessica Taylor, 20
- Remains belonging to Jessica Taylor, a 20-year-old woman working as an escort in New York City, were found in a wooded area in Manorville on July 26, 2003. Her additional remains — initially labeled “Jane Doe No. 5” — were discovered on March 29, 2011, along Ocean Parkway.
Valerie Mack, 24
- Valerie Mack was 24 years old and living in Philadelphia when she went missing. She worked as an escort, using the alias “Melissa Taylor.” Relatives last saw Mack in the spring or summer of 2000 in Port Republic, New Jersey, but she was never reported as missing to the police. Her partial skeletal remains were found in Manorville in September 2000 but were initially known as “Jane Doe No. 6.” More bones were found on April 4, 2011, along Ocean Parkway.
Unidentified Asian man
- The skeletal remains of a yet-to-be-identified Asian man were found along Ocean Parkway on April 4, 2011. It is estimated that the man was between 17 and 23 years old at the time of his death. He was approximately 5 feet 6 inches tall with bad teeth.
‘Peaches’ and her daughter
- An African American woman’s partial remains were discovered in Hempstead Lake State Park back in 1997, and she had become known as “Peaches” because of a bitten tattoo of a peach on her left breast. On April 4, 2011, police uncovered the remains of a toddler, who was about 2 years old at the time of her death. DNA testing confirmed that one of the skeletons was that of the 2-year-old girl’s mother, “Peaches.”
Karen Vergata
- A victim previously referred to as Jane Doe No. 7 has been identified as 34-year-old Manhattan woman Karen Vergata. Vergata is believed to have disappeared around Feb. 14, 1996; two months later, her legs were found in a plastic bag at a park near Fire Island’s Blue Point Beach. At the time of her disappearance, Vergata was believed to have been working as an escort. Two sets of Vergata’s remainswere identified in August 2023.
Shannan Gilbert, 23
- Gilbert was a Craigslist escort who lived in Jersey City, traveled with her driver Michael Pak from Manhattan to meet a client, Joseph Brewer, at his home in the Oak Beach Association on the morning of May 1, 2010. She spoke with two neighbors before disappearing. Her body was discovered in a marsh near Oak Beach — about half a mile from where she was last seen alive — on December 13, 2011.
Jessica Taylor, 20
- Taylor, a 20-year-old woman working as an escort in New York City, were found in a wooded area in Manorville on July 26, 2003. Her additional remains — initially labeled “Jane Doe No. 5” — were discovered on March 29, 2011, along Ocean Parkway.
Sandra Costilla
- Costilla was murdered in 1993 but had not been included among the so-called Gilgo Beach victims — until now. Investigators suspected convicted serial killer John Bittrolff in Costilla’s death, but he was never charged in her slaying — which remains one of several unsolved Long Island murders.
According to a bail application filed by prosecutors Thursday, Heuermann maintained a secret digital record titled “HK2002-2004” on his computer since at least 2000, keeping precise notes on the murders.
The digital document was broken up into specific sections like “Problems,” “Supplies,” “TGR,” which prosecutors said are believed to be potential targets, and “DS,” allegedly for “dump sites.”
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The sick how-to file notes that “small is good” for potential victims, and includes a three-part section for “Pre-Prep,” “Prep” and “Post-Event,” the Suffolk DA’s court document said.
“The HK planning document continues to further expound on preparatory measures such as specific ‘recon’ steps taken,” including “packaging [a body] for transport,” prosecutors said.
One section notes to “remove head and hands,” which the DA’s office said is consistent with the remains of Taylor and another Gilgo body, Valerie Mack, which has not been officially tied to Heuermann.
Also included is a section reminding the accused killer to “remove ID marks [tatoos] [sic],” which is consistent with Taylor’s remains, which had “linear injuries,” particularly “around where Ms. Taylor’s tattoo had been located, which investigators believe was intended to inhibit the identification” of the victim.
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Finally, Heuermann allegedly kept a “Things to Remember” section, which detailed twisted reminders such as to “hit harder” for “next time” and to use heavier rope because the “light rope broke under [stress of being tightened].”
“Hit harder too many hit to take down,” the planning document says, according to prosecutors.
“Consider a hit to the face or neck next time for take down.”
In addition, Heuermann opines on the importance of sleep to avoid “problems” and increase what he refers to as “play time,” prosecutors said.
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Also in that section are notations for “push pins to hang drop clothes from ceiling” and “not tape,” and notes on “sound travel” — indicating a preference for committing crimes indoors, the DA said.
According to prosecutors, the HK file “points to Heuermann’s self-education and ‘homework.'”
Heuermann, a 60-year-old architect from Massapequa Park with offices in Midtown Manhattan, is charged with killing a half-dozen sex workers over the past three decades.
The murders of the victims — Taylor, 20, Megan Waterman, 22, Melissa Barthelemy, 24, Maureen Brainard-Barnes, 25, Amber Lynn Costello, 27, and Costilla, 28 — remained unsolved for decades until the slayings were reopened in 2022 and led to Heuermann’s arrest in July.
Costilla, who disappeared in 1993, had not previously been tied to the other bodies found along Ocean Parkway, where six other bodies were found, cases that remain unsolved.
Costilla was initially believed to be tied to convicted serial killer John Bittrolff, but the documents filed Thursday by prosecutors said her DNA did not match him.
