Gilgo Beach serial killer suspect Rex Heuermann is expected to change his plea to guilty on Wednesday

Rex Heuermann, the man accused of being the Gilgo Beach serial killer, is expected to plead guilty to multiple murders when he appears in a Riverhead court on Wednesday.

It's a potentially pivotal moment in a case that has gripped Long Island for decades.

Why Rex Heuermann would change his plea

Heuermann has stood stone-faced in one court appearance after the other, firmly denying he is the long-sought Long Island killer.

The 62-year-old is expected Wednesday to announce a stunning reversal, changing his claims of innocence to guilty pleas in all seven murders he is charged with -- and an eighth unsolved murder. All the victims were sex workers, their body parts dumped in desolate locations decades ago, including Gilgo Beach.

Heuermann is expected to admit to each murder in court, but with no trial, victims' families may not get the answers they are seeking. Sources say that's one of the reasons for his decision to plead guilty -- to avoid a trial and all its details, for himself and his family.

Heuermann has been in near solitary confinement 23 hours per day, protective custody, since his arrest nearly three years ago.

A plea will end years of fear and speculation, but questions linger.

The arrest of Rex Heuermann and key evidence

The arrest of Heuermann, a Massapequa father and architect, in 2023 ended a hunt which many feared would never catch the prolific killer. Ten sets of human remains have been unearthed after the disappearance of Shannan Gilbert in 2010.

At the time, then-Suffolk County Police Chief Rodney Harrison and defense attorney Michael Brown offered vastly different characterizations of the accused.

"Rex Heuermann is a demon that walks among us, a predator that ruined families," Harrison said.

"The only thing he said, in tears, [was] 'I didn't do this,'" Brown said.

For years, it was a cold case mystery, but the break came when investigators returned to overlooked evidence and found a unique truck -- a green Chevy Avalanche, which was seen by a victim's roommate and owned by Heuermann in Massapequa Park, where the victim's phones last pinged.

Later, DNA was found on a pizza crust Heuermann threw away, matching hair found on the victims.

"So in this particular case, the whole genome sequencing allowed them to have a much larger amount of information," said April Stonehouse, a professor of forensic science at Arizona State University. "Basically, it's a further interrogation method, meaning that we would get more data from the sample. And so in this particular case, because the hairs were so old ... The DNA could have been broken down. So this is a more intensive technique to be able to get DNA information from it."

Weeks of scouring Heuermann's house turned up digital evidence of obsessive online searches for sexual violence and the Gilgo murders and, plus a chilling planning document on how to kill and avoid detection.

Serial killings are happening less and less, expert says

"I think Heuermann may go down as the last serial murder case in American history because of changes in technology. You don't have these sorts of murders over the spans of years," said Neama Rahmani, a former federal prosector.

Rahmani says today's DNA and high-tech surveillance gives law enforcement the upper hand.

"The burner phones, the mitochondrial DNA, Heuermann is a very large individual and he is easy to spot, very distinctive vehicle. Someone like this would not get away with it," Rahmani said.

Heuermann's ex-wife refutes wrongful death lawsuit

Heuermann's ex-wife, Asa Ellerup, and her daughter with Heuermann have been named in a wrongful death lawsuit that was brought by the son of victim Valerie Mack.

"His family knew or should have known what was going on in that basement," attorney John Ray previously said, "which the police department have confirmed that these girls were being tortured and slaughtered in his own house -- a 1,343 square-foot house. It is impossible to believe the family didn't know what was going on it that house."

Ellerup and her daughter held a news conference on Wednesday afternoon, where their attorney, Robert Macedonio, blasted the lawsuit as "reckless."

"The individual responsible acted alone. Rex Heuermann has been indicted and charged with a series of homicides and he will have his day in court to answer his charges, which we all know will be tomorrow morning," Macedonio said. "My clients have fully cooperated with law enforcement from the very beginning. There is no evidence that implicates them in any way. None. Unfortunately, there has now been a civil lawsuit filed that attempts to suggest otherwise. The lawsuit is reckless, irresponsible, and completely, completely, unsupported by the facts of this case."

Neither Ellerup nor her daughter spoke during the news conference. Macedonio said they would issue a statement following Wednesday's events.