The case against suspected Gilgo Beach serial killer Rex Heuermann is building as sources confirm to News 12 that additional charges against him are expected this week.

The Massapequa Park father of two is accused of first- and second-degree murder in the deaths of Melissa Barthelemy, Megan Waterman and Amber Costello. He is also charged with second-degree murder in the killing of Maureen Brainard-Barnes.

Police are still investigating six other sets of remains that were discovered near Gilgo Beach in 2011—an unidentified Asian man, an unidentified mother and toddler, and the partial remains of Karen Vergata, Valerie Mack and Jessica Taylor.

Last month, investigators made a surprise return to Heuermann’s home for a second search. It lasted nearly a week, and detectives were seen carrying out multiple boxes of potential evidence.

In April, police scoured an area in Manorville where body parts of Mack and Taylor were discovered more than two decades ago.

In 2000, police found Mack’s torso near Halsey Manor Road. Three years later, Taylor’s torso was discovered just a mile away. The two women became part of the Gilgo Beach murders investigation when police found more of their remains along Ocean Parkway in 2011.

Law enforcement experts said these victims could change the course of the investigation.

“These victims were dismembered, so it could open up whole other charges, meaning they’re going to look at other homicides that they could link to Rex,” said Michael Alcazar, a retired NYPD detective and adjunct professor at John Jay College of Criminal Justice.

When asked if the recent searches of Manorville and Heuermann’s home resulted in the new charges, Suffolk County District Attorney Ray Tierney said, "There were a number of necessary investigative steps that were taken. You pointed out just some of them, and Thursday you will see the fruits of that investigation."

Heuermann’s wife, Asa Ellerup, is not expected to attend the court appearance on Thursday. Her attorney said she is still out of state.