Alleged Gilgo Beach serial killer's 'how to kill' doc revealed: prosecutors

Rex Heuermann, the accused Gilgo Beach serial killer, allegedly kept a 'blueprint' of his crimes, prosecutors say.

Heuermann, 60, was back in a Suffolk County Courthouse on Thursday to face additional charges in the killings of Jessica Taylor and Sandra Costilla, two women who were long suspected of being the victims of men preying on sex workers.

Investigators discovered a "planning document" on the hard drive found in Heuermann's basement that they believe he used to "methodically blueprint" his killings, prosecutors said.

What's in the document? 

The document includes Heuermann’s concerns about leaving behind forensic evidence, how to "improve" "next time" and guidance for cleaning and washing bodies, according to the bail application.


Rex Heuermann appears in court on Thursday, June 6. 

The New York architect was previously accused of killing four women and leaving their corpses scattered along a coastal Long Island highway.

Prosecutors said an analysis of Heuermann’s computers confirmed the planning document was in an "unallocated space" and had hence been deleted, which is consistent with his use of forensic wiping software. 

Police find tapes, phones, hard drives

Police recovered 15 cameras, 27 computers, 58 internal hard drives, 46 phones, 9 Wi-Fi routers, 17 tablets, 42 USB devices, 36 SIM cards, hundreds of CDs and tapes belonging to Heuermann.

The task force says an extensive analysis is still underway as some devices are encrypted.


Gilgo Beach, N.Y.: In this view looking east along Ocean Parkway in Gilgo Beach, New York, the area where the bodies of four women were found is shown to the left of the parkway on July 25, 2023. Investigators have connected at least three of those b

Investigators also found violent pornography, and images "consistent with the crime scenes" of the victims, Costilla and Taylor.

Police also recovered a copy of one of John Douglas’ books on criminal psychology and notes referencing other ones.

The investigation remains ongoing. 

Who is Sandra Costilla? Jessica Taylor?

Heuermann, the alleged Gilgo Beach serial killer, was charged with two more killings on Thursday morning on Long Island: Sandra Costilla and Jessica Taylor.

In a court filing, prosecutors said they were able to use new forensic testing methods to match hairs found on or near the vicinity of both victims to a DNA profile that is a likely match to Heuermann.

Jessica Taylor


Courtesy of Jessica Taylor’s family

Heuermann was arraigned in connection with the July 2003 dismemberment death of 20-year-old escort Jessica Taylor.

According to police, Taylor was found decapitated with her arms severed from her body (around July 26, 2003).  Police also said a tattoo on her body had been "severely obliterated by a sharp object." 

During the initial investigation in Manorville in 2003, the victim’s head, arms, and hands were not found at the scene and their location remained unknown to law enforcement for nearly eight years. 

According to court documents, The Gilgo Homicide Task Force has established a pattern that Heuermann’s wife and children were out of state at the time of Taylor’s disappearance and murder, "a consistent theme in each of the charged homicides thus far."

Sandra Costilla

Heuermann was indicted in the November 1993 death of Sandra Costilla, a Queens woman whose remains were found in the town of Southampton over three decades ago. 

According to police, Costilla was found lying on her back with her arms outstretched over her head with her uncovered legs spread apart. 

She was also found with sharp force injuries to her face and her body. 

Costilla was a native of Trinidad and Tobago but had been living in New York prior to her disappearance and murder.

The Associated Press contributed to this report.