Disturbing new details have emerged in the Gilgo Beach serial killings as Rex Heuermann, 60, was charged in two additional women.

The new charges also significantly expand the timeline in the Gilgo Beach case, with the first murder Heuermann is accused of committing now taking place in 1993.

Prosecutors also revealed disturbing "planning" documents that they allege the suspect used in his killings and disposal of the victims.

The architect and father allegedly "meticulously planned and executed six separate murders," Suffolk County District Attorney Raymond Tierney said at a news conference Thursday.

Heuermann appeared before a judge on Long Island to face charges in the killings of Jessica Taylor and Sandra Costilla, two young women who were long suspected of being the victims of men preying on sex workers.

Listen to our latest "Eyewitness News to Gilgo Beach" episode and make sure you follow us to catch future episodes or listen to our archives explaining the case as only New York's Eyewitness News can.

Learn more about your ad choices. Visit podcastchoices.com/adchoices