The man accused of killing sex workers and dumping their bodies along a coastal parkway on New York’s Long Island was charged Tuesday in the death of a fourth woman.

Rex Heuermann, a former architect, was formally charged with second-degree murder in the killing of 25-year-old Maureen Brainard-Barnes – the last of the so-called “Gilgo Four” murders that police have officially tied to Heuermann.

Brainard-Barnes’ body was found in 2010 along a remote parkway near Gilgo Beach three years after she vanished, according to court records.

Last July, Heuermann, 60, was named the prime suspect in her death when he was arrested and charged with the slayings of Megan Waterman, 22, Melissa Barthelemy, 24, and Amber Costello, 27 – all of whom, like Brainard-Barnes, were found along the same stretch of parkway.

Ten sets of human remains have been found buried in the Gilgo Beach area of Jones Beach Island. The majority of the cases remain unsolved and investigators don't think Heuermann is responsible for all the killings. A grand jury task force was set up in recent years to investigate the cases, including the deaths of the four women.

Heuermann entered a not guilty plea on the latest charges, according to the Associated Press.

Investigation into 'Gilgo Four' murders is over, district attorney says

Suffolk County District Attorney Raymond Tierney at a news conference on Tuesday said the new charges mark the end of the investigation into the deaths of the four women.

"The grand jury investigation of the so-called Gilgo Four is over [and] has been concluded," Tierney said. "We will proceed with those cases in court."

Meanwhile, the task force will carry on with its investigations into the deaths of the other people whose remains were discovered in the Gilgo Beach area.

"There should be no mistake the work of the grand jury is continuing," he said. "In regard to those other bodies and those other murders, the task force will continue to investigate those cases."

Timeline:What led to the arrest of suspect Rex Heuermann in Long Island

How was Heuermann caught?

Brainard-Barnes, a Connecticut mother of two, disappeared in 2007 after she headed to Manhattan for sex work, according to friends who became concerned when she uncharacteristically stopped using her phone.

After the many remains were discovered in the Gilgo Beach area, police began chasing down leads. It wasn't until March 2022 that Heuermann was first connected with the case when police linked him to a Chevrolet Avalanche pickup truck that a witness reported seeing in 2010.

Investigators searched phone and bank records and began to find more connections between Heuermann and the murders. Heuermann used his American Express card in the same area where a burner phone was used to contact the victims, according to court records. He allegedly used one of the phones to call and taunt relatives of Barthelemy after she went missing.

“Significantly, investigators could find no instance where Heuermann was in a separate location from these other cellphones when such a communication event occurred,” court records said.

In January of last year, a surveillance team following Heuermann saw him throw a pizza box into a garbage can outside his office. Police found pizza crust inside the box and sent it to a forensic lab for analysis. In June, the lab returned results saying the swab from the crust matched a hair found where the women's bodies were discovered.

He was arrested outside his Manhattan office in July. Later that month, his wife, Asa Ellerup, filed for divorce.

Contributing: Associated Press; Jeanine Santucci, John Bacon, Jorge L. Ortiz, USA TODAY