A judge denied a request by Heuermann's defense to for multiple trials for seven murders that occurred over 17 years in remote parts of eastern Long Island.

Rex Heuermann, of Massapequa Park, Long Island, is charged with killing four women in New York. Photo courtesy of the Suffolk County Sheriff's Office UPI

Sept. 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.

The ruling by Timothy Mazzei is the latest in the run-up to the expected trial of Heuermann, who is accused of killing seven women suspected of being sex workers and whose remains were found in secluded areas of Ocean Parkway near Gilgo Beach and parts of eastern Long Island.

Heuermann earlier pleaded not guilty to the charges. His defense argued that his first three murder charges should be tried separately from the others because of the length of time between the killings and the locations of where the bodies were found, reported WABC-TV.

However, Judge Timothy Mazzei ruled there would be one trial for all the charges.

Prosecutors have sought one trial for Heuermann, arguing that he came familiar with the area where the murder allegedly took place while working as seasonal employment at Jones Beach State Park between 1981 and 1984, the station reported.

Prosecutors have argued that Heuermann kept detailed notes about the serial killings, body disposal and torture pornography.

"I think a big consideration by the court which was stated by their decision was that planning document and that planning document talks about murders that had occurred, and are going to occur in the future," Suffolk County District Attorney Ray Tierney told WABC-TV.

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. Michael Brown, Heuermann's defense attorney, called the DNA evidence "magic" and had tried unsuccessfully earlier to have it thrown out because it was untested in New York Courts.

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. His next court date is Jan. 13, 2026.