The horrifying details surrounding confessed Gilgo Beach serial killer Rex Heuermann continue to emerge, with a newly released documentary episode exposing what investigators and experts describe as a chillingly organized “four-day kill plan” allegedly used during his years-long murder spree on Long Island.

The revelations were featured in the final episode of Peacock’s documentary series The Gilgo Beach Killer: House of Secrets, which aired shortly after Heuermann pleaded guilty to murdering seven women and admitted responsibility for the death of an eighth victim.

The episode provided disturbing new insight into how prosecutors believe the 62-year-old architect carefully planned, carried out, and concealed the killings that terrorized Long Island communities for decades.

According to therapist Alison Winter, who met extensively with Heuermann while he was in custody, the confessed killer described a structured routine that revolved around four separate days. The process, she said, became increasingly refined over time as he sought to avoid detection.

Winter explained that the first day was dedicated entirely to preparation. Heuermann allegedly cleaned and organized the basement of his Massapequa Park home, which prosecutors and family members later described as a “kill room.” According to the documentary, he would prepare tools, plastic coverings, and other materials before bringing victims into the house.

“He cleaned the basement and prepared for his time,” Winter said during the episode, describing the room as the center of the crimes.

On the second day, Winter claimed Heuermann spent time with the victims before murdering them. She described his behavior during these encounters as manipulative and calculated.

“It was always enjoyable and he was kind,” she said, adding that the violence unfolded only later.

After the killings, investigators believe Heuermann engaged in what prosecutors previously called “post-mortem play time,” a detail allegedly referenced in a planning document found on his computer. Suffolk County District Attorney Ray Tierney has repeatedly described the document as a blueprint for murder.

The third day allegedly focused on disposal and cleanup. Winter said Heuermann would transport remains to dump sites near Gilgo Beach and surrounding areas before eliminating evidence connected to the crimes.

“He gathered the tools, the tarp, the clothing,” Winter explained. “Everything had to disappear so there was no evidence, in his mind.”

According to the documentary, Heuermann even timed himself while disposing of bodies, using a stopwatch to reduce the amount of time spent at dump locations. Winter claimed that during earlier killings it took him more than two minutes to unload remains, but by the final murder he had shortened the process to just 37 seconds.

“He was meticulous, detail-oriented, and pathological,” she said. “Clearly, he enjoyed killing. It became an obsession for him.”

The fourth day, according to Winter, functioned as a “buffer day” in case complications arose after the murders. She described the cycle as “a four-day adrenaline rush” before Heuermann returned to his normal suburban family life.

Those revelations stunned viewers and added to the growing horror surrounding the case, especially after Heuermann’s former wife, Asa Ellerup, publicly confirmed that several victims had been murdered inside the family home.

During the documentary, Ellerup revealed that she now sleeps in the remodeled basement room where investigators believe the killings occurred.

“The brutal truth is that Rex Heuermann dismembered bodies in this room,” she said during an emotional scene. “That is the brutal truth.”

Ellerup explained that she completely renovated the basement after Heuermann’s arrest, replacing floors, walls, doors, and moldings. The room now contains stuffed animals, floral decorations, and bright furniture, a stark contrast to the horrific acts prosecutors say occurred there.

Still, she admitted the trauma remains overwhelming.

“Every night when I go to sleep, I am haunted by dreams,” Ellerup said. “It will never go away. It will follow me for the rest of my life.”

Their daughter, Victoria Heuermann, also appeared in the documentary and shared additional disturbing details. According to her, one victim was allegedly killed in her parents’ bedroom rather than in the basement.

“My dad confirmed that one of them was killed in their bed,” she said.

The documentary also captured the moment Ellerup confronted her former husband after his confession. She recalled him appearing “very nervous” when she asked how many women he had killed.

“Eight,” he allegedly answered.

Heuermann formally pleaded guilty in a Riverhead courtroom after years of denying responsibility for the murders. During the hearing, prosecutors asked him one by one whether he intentionally murdered victims Melissa Barthelemy, Megan Waterman, Amber Costello, Maureen Brainard-Barnes, Jessica Taylor, Valerie Mack, Sandra Costilla, and Karen Vergata.

Each time, Heuermann quietly responded, “Yes.”

Prosecutors said the victims were targeted over nearly two decades. Most were young women working as sex workers whose remains were discovered along Ocean Parkway near Gilgo Beach beginning in 2010.

Authorities believe Heuermann used burner phones to contact victims and lure them with promises of money before strangling them and disposing of their remains.

Some victims were dismembered before their bodies were scattered across Long Island.

District Attorney Tierney described Heuermann as a predator who carefully maintained the image of an ordinary suburban father while secretly carrying out brutal killings.

“This defendant walked among us, playacting as a normal suburban dad,” Tierney said after the guilty plea. “He thought that by killing them, he could silence them forever.”

He added that evidence left behind by the victims ultimately led investigators to the truth.

The case remained unsolved for more than a decade before investigators linked Heuermann to the murders using DNA evidence, cellphone records, and surveillance data. He was arrested in July 2023 outside his Manhattan office.

Since then, the case has generated intense public fascination, particularly because of the double life Heuermann appeared to lead. Friends, neighbors, and even family members have repeatedly said they never suspected he could be capable of such violence.

Attorney Robert Macedonio, who represents Ellerup and Victoria, emphasized after the plea hearing that neither woman had any knowledge of the crimes.

“Rex Heuermann, and Rex Heuermann alone, is responsible for these horrific crimes,” Macedonio said. “Any suggestion that Asa Ellerup or Victoria Heuermann were involved is irresponsible.”

He also noted that the family continues to struggle emotionally as they attempt to process the revelations.

At sentencing, Heuermann is expected to receive multiple consecutive life sentences without the possibility of parole.

His guilty plea also requires him to cooperate with the FBI’s Behavioral Analysis Unit, which continues studying his crimes and psychological profile.

Meanwhile, investigators and victims’ families are still searching for answers in a case that shattered lives across Long Island for decades.

For the loved ones left behind, the confessions may have brought some closure — but the pain remains permanent.

As Tierney told reporters after the plea hearing, “While we mourn the loss of these victims, we are grateful they were never forgotten. Their stories ultimately exposed the man responsible.”