Gilgo Beach murder suspect expected to be charged in death of 4th woman: Sources

Rex Heuermann is already charged with killing three women. He will return to court on Tuesday.

Alleged serial killer Rex Heuermann returns to court next week on Long Island where he is expected to be charged in the death of a fourth woman whose remains were found in a marshy spot near Gilgo Beach, multiple sources told ABC News.

Heuermann, 60, is already charged with killing three women whose bodies were found wrapped in burlap in close proximity and prosecutors have said he is the prime suspect in the death of a fourth, Maureen Brainard-Barnes.

Heuermann has pleaded not guilty to killing Megan Waterman, Melissa Barthelemy and Amber Costello, all of whom were found dead in December 2010. He is being held without bail.

He is due back in court in Riverhead Tuesday when prosecutors are expected to announce that a grand jury has returned an indictment charging him with a fourth murder, the sources said.