D.A. Fingers Accused Gilgo Killer Rex Heuermann in Valeria Mack Death; Stomach-Churning Notes Kept About Grisly Murders Sparked Breakthrough

In a shocking revelation, officials disclosed that accused Gilgo Beach serial killer Rex Heuermann meticulously documented his heinous crimes in a stomach-churning "planning document," RadarOnline.com has learned.

This file included sections such as "Things to Remember" and "Lessons Learned," shedding light on the meticulous planning of the grisly slayings.

Suffolk District Attorney Ray Tierney spoke with News 12 ahead of the one-year anniversary of Heuermann’s arrest in the Gilgo serial killer case.

Tierney told the outlet that investigators are still combing through evidence which includes physical and digital evidence. The D.A. says Heuermann had hundreds of encrypted smart devices. Detectives are working to access the information on those devices.

The Suffolk County prosecutors unveiled that Heuermann, a New York City architect and family man, meticulously recorded the details of his vicious murders spanning back to 1993.

This included the decapitation and mutilation of victims, with additional charges recently added in connection to the slaying and dismemberment of more individuals.

One of the most chilling aspects of the planning document was Heuermann's indication to keep killing, with references to "next time," revealing his prior experience and the changes he envisaged for upcoming crimes.

The file meticulously detailed preparatory measures and disturbing notes on "body prep" and the selection of victims.

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 such as “Problems,” “Supplies,” “TGR,” which prosecutors said are believed to be potential targets, and “DS,” allegedly for “dump sites.”

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Heuermann's arrest in connection to the "Gilgo Four" victims shed light on the long-unsolved Gilgo Beach murders, where petite female sex workers, along with other individuals, were found brutally slain. He is also a suspect in a seventh murder in the killing of Valerie Mack.

The arrest was a breakthrough following years of investigation into the mysterious deaths that shook the community.

The unraveling of Heuermann's disturbing planning document added a new layer to the unsolved murders that plagued the Long Island area for decades.

The meticulous nature of the document and its references to past crimes and potential future actions pointed toward a disturbing pattern in the accused killer's behavior.