Long Island serial killer Rex Heuermann will spend the rest of his life behind bars — but not before getting an earful from the families he ravaged.

Heuermann, who is in Suffolk County court Wednesday to be slammed with three life sentences for the savage murders of eight sex workers between 1993 and 2010, has to first listen to victim impact statements from more than a dozen relatives of the women he strangled and butchered.

The hulking Manhattan architect, 62, pleaded guilty in April to the heinous murders — all but one of which unfolded in a basement “kill room” in his family’s Massapequa Park home.

He entered the courtroom wearing a black suit — and sporting the same sinister stare he wore in a new mug shot released this week by the Suffolk County Sheriff’s Office.

Outside the Riverhead courthouse, a group of sex workers protested against the killer.

The fiend’s plea deal with Suffolk County prosecutors called for the three life sentences — and his sentencing Wednsday closed out a national-headline-grabbing case involving a grisly string of killings that haunted the region for decades.

Heuermann confessed to killing eight women between 1993 and 2010 and dumping their broken bodies along desolate stretches of Long Island, where they were found starting in December 2010.

But the cases remained unsolved for decades until the investigation was reopened in 2022 and led to Heuermann’s arrest the next year — partly thanks to a pizza box he tossed in the trash outside his Manhattan office.

In April, the confessed killer admitted he murdered all but one of his victims in a basement “kill room” in the family home while his wife and two kids were away, eventually developing a meticulous four-day routine to plan his crimes, clean up afterward and dispose of the bodies.

He kept a Tinder account and buzzed prostitutes on burner phones more than 500 times while also embarking on “significant searches for pornography related to bindings, torture, rape, snuff videos, crying, bruised and impaled women and/or girls,” authorities said.

Some of the victims were dismembered and wrapped up in burlap before being dumped.

The killings remained a dark mystery until former NYPD Chief Rodney Harrison took over as Suffolk County police commissioner and reopened the cases in 2022.

Heuermann was arrested in July 2023 outside his office and charged with three of the cold-case killings, with DNA evidence later linking him to four more women — and eventually another in a surprise development.

The 6-foot-4 architect confessed to killing Amber Lynn Costello, 27; Megan Waterman, 22; Melissa Barthelemy, 24; and Maureen Brainard-Barnes, 25, who were famously known as the “Gilgo Four” — as well as Valerie Mack, 24; Jessica Taylor, 20; and Sandra Costilla, 28, the first victim killed in 1993.

He also copped to killing Karen Vergata, 34, whose 1996 murder had not been linked to him.

Michael Brown, Heuermann’s lawyer, told reporters that his client was not involved in two other Gilgo Beach slayings — Shannon Gilbert, a sex worker who disappeared in 2010, and an unidentified victim known only as “Asian Doe.” 

Suffolk County officials said Heuermann has been held in solitary confinement at the county jail since his arrest, whittling away his time with books and the occasional outdoor time in the jail yard — alone.

Sources revealed that the killer has also found a sympathetic pen pal while locked up — Keith Jesperson, the notorious “Happy Face Killer,” who is serving a life sentence at the Oregon Correctional Facility.

Jesperson, a truck driver who got the moniker for signing taunting letters to cops and media outlets with a smiley face, was arrested in 1995 and confessed to killing eight women between 1990 and 1995 in California, Washington, Oregon, Florida, Nebraska and Wyoming.

Jesperson said he advised Heuermann “not to go to trial” following the hulking architect’s 2023 bust, and urged him not to waste time going through a high-profile trial, the Daily Mail reported.

This is a developing story