Eric Fischer, 23, entered the plea at an arraignment Thursday on a 25-count indictment that included charges of third-degree rape, third-degree criminal sexual act and endangering the welfare of a child, said a spokeswoman for the Suffolk County district attorney's office.
He allegedly contacted his victims using a Gothic culture Web site called vampirefreaks.com and then arranged to meet them in Long Island cemeteries, prosecutors said.
Fischer was first arrested in March and charged with third-degree rape and third-degree criminal sex act for an incident involving a 16-year-old girl he met on the Web site, police said. A month later, Fisher was accused of luring someone he believed was a 13-year-old girl — but who turned out to be a detective in the Suffolk police computer crimes squad.
Suffolk Assistant District Attorney Julie Walsh said a further investigation uncovered five other victims, ranging in age from 14 to 16.
Fischer's attorney declined to comment.