Rex Heuermann, of Massapequa Park, Long Island, is charged with killing four women in New York. Photo courtesy of the Suffolk County Sheriff's OfficeSept. 23 (UPI) -- Accused Gilgo Beach serial killer Rex Heuermann saw a setback in court Tuesday after a judge refused to try each of his charges separately and again allowed DNA evidence. Mazzei also ruled that prosecutors can also use DNA evidence in their case against Heuermann, a 61-year-old architect, reported the New York Post. The DNA evidence is key to prosecutors' case and uses advanced science to test damaged samples, according to the Post. While prosecutors say they are ready for the trial, Tierney told WABC-TV that he is expecting the defense to file more motions that will delay the trial.