Rex Heuermann, the man who has been charged with the murders of three sex workers on Gilgo Beach, New York, is expected to be charged with a fourth murder, according to a person with direct knowledge of the situation.

Suffolk County District Attorney Raymond Tierney will announce the new charges Tuesday after they are unsealed at the Suffolk County Courthouse in Riverhead on Long Island.

Authorities have said that Heuermann, 60, is the prime suspect in the death of Maureen Brainard-Barnes but that they did not have enough evidence to charge him in that case at the time of the other charges. 

A lawyer for Heuermann did not immediately respond Sunday night to an emailed request for comment on the new charges.

Heuermann was arrested in July as detectives surrounded him outside his Manhattan architecture office. He was charged with the deaths of Melissa Barthelemy, 24; Megan Waterman, 22; and Amber Lynn Costello, 27, all found in high weeds near Gilgo Beach, on the south shore of Long Island.

Following Heuermann’s arrest in connection with the killings of Barthelemy, Waterman and Costello, he was considered to be the prime suspect in Brainard-Barnes’ murder, and authorities had “substantial evidence” of his involvement in the case, said a bail application obtained by NBC News at the time.

The remains of all four women — known as the “Gilgo Four” — were discovered in December 2010 when authorities were searching for Shannan Gilbert, another sex worker who disappeared around that time.

All four women were discovered along a stretch of Ocean Parkway.

Heuermann was connected to the deaths through DNA obtained from a discarded slice of pizza found in trash outside his office, authorities said. His wife’s hair was also found at the crime scenes, leading investigators to believe items used in the slayings, including burlap sacks and tape, came from the residence they shared.

Heuermann pleaded not guilty in July to three charges of first-degree murder and three charges of second-degree murder in the killings of Barthelemy, Waterman and Costello. He broke down emotionally as he was officially read the charges in court and was ordered held without bail.

11 bodies discovered

Although Gilbert’s remains were not discovered until December 2011, authorities found the remains of 11 other bodies in the search for her.

Barthelemy’s remains were found first on Dec. 11, 2010. Two days later, three more bodies turned up in the search: those of Waterman, Costello and Brainard-Barnes.

Partial remains of Jessica Taylor were found along Ocean Parkway in March 2011.

The next month, three additional bodies were discovered: those of Valerie Mack, 24, a female toddler and a man. Mack was not identified until 2020.

Partial remains of Taylor and Mack had also been found years earlier in Manorville, about 45 miles east of Gilgo Beach, police said.

Two more bodies were then found in Nassau County, where Heuermann lives.

Barthelemy, Waterman, Costello, Brainard-Barnes, Gilbert, Taylor and Mack were all sex workers. Heuermann has not been charged in the deaths of Gilbert, Taylor or Mack.

In an interview with NBC’s “Dateline” in November, Suffolk County Police Commissioner Rodney Harrison said authorities are investigating potential links between Heuermann and the other victims.

“One thing we’re not going to do is rule out any of those bodies that were found out on Ocean Parkway,” he said.