RIVERHEAD, N.Y. (AP) — Prosecutors say they are planning a major announcement in their investigation of the suspected serial murders of a group of women whose bodies were found strewn along a coastal highway near Long Island’s Gilgo Beach.

The prime suspect in some of those killings, Rex Heuermann, is due in court Tuesday, months after he was charged in the deaths of three women. Prosecutors had also said they were working to charge him with a fourth slaying.

Suffolk County District Attorney Ray Tierney is set to make the announcement after a court hearing in the case in Riverhead, New York.

Heuermann was charged in July with the killings of Melissa Barthelemy, Megan Waterman and Amber Costello, whose bodies were found buried along a remote beach parkway. Prosecutors said Heuermann is also suspected in the death of Maureen Brainard-Barnes, who vanished in 2007.

He has pleaded not guilty and has been held without bail at Suffolk County Jail in Riverhead.

The arrest of Heuermann, a 60-year-old architect, came more than a decade after police searching for a missing woman found 10 sets of human remains hidden in the thick underbrush near Gilgo Beach.

The deaths had long stumped investigators and fueled immense public attention on Long Island and beyond, with the killings leading to the 2020 Netflix film “Lost Girls.” Authorities suspected that a serial killer committed some of the slayings but have said they don’t believe all the victims were killed by the same person. The majority of the killings are still unsolved.

Heuermann was first identified as a suspect in 2022 when detectives linked him to a pickup truck that a witness reported seeing when one of the victims disappeared.

The following year, detectives tailing Heuermann recovered his DNA from pizza crust in a box that he discarded in a Manhattan trash can and matched it to a hair found on a restraint used in the killings, authorities said.

Heuermann had worked as a licensed architect with a Manhattan-based firm and lived in Massapequa Park, a suburb close to the spot where the bodies were found.