Editor’s Note: Find Tuesday’s story on the Gilgo Beach serial killings here.

CNN  — 

Investigators have received a flood of evidence and information related to the suspect charged in some of the Gilgo Beach killings since his arrest Thursday, the Suffolk County District Attorney told CNN on Monday.

“We feel we can prove these three murders,” Ray Tierney said on “CNN This Morning.”

Rex Heuermann, 59, was arrested and charged with murder in the killings of three of the “Gilgo Four,” a group of women whose remains were unearthed near Long Island’s Gilgo Beach in 2010. He has pleaded not guilty to the killings of Melissa Barthelemy, Megan Waterman and Amber Costello.

He is also the prime suspect in the 2007 disappearance and killing of the fourth woman, Maureen Brainard-Barnes, according to a bail application from prosecutors, though he has yet to be charged in