Facing a mountain of lurid evidence and an approaching trial that seems primed to reignite the intense interest surrounding his case, a lawyer for Rex Heuermann, who has been charged with murdering seven women around Gilgo Beach on Long Island, offered a glimpse of his legal strategy on Wednesday in a Riverhead, N.Y., courtroom.

The lawyer, Michael J. Brown, has asked the judge in the case to toss out DNA evidence seen as central to the prosecution. He also wants the case broken up into five separate trials.

On Wednesday, the judge in the case, Justice Timothy P. Mazzei, said he would hold two hearings to consider the lawyer’s requests.

In addition to Mr. Heuermann’s phone records and internet activity, prosecutors are basing much of their case on cutting-edge nuclear DNA findings. They say the evidence links strands of hairs found with most of the Gilgo Beach victims to Mr. Heuermann, who appeared in court on Wednesday morning wearing a dark suit.

Mr. Brown made it clear that he would do all he could to undermine the DNA evidence. Speaking to reporters after Wednesday’s hearing, he disparaged the findings as “magic,” not science, and said they hinged on methodology that had not been deemed reliable as criminal evidence in New York State.

Ray Tierney, the Suffolk County district attorney, who is prosecuting the case, described the evidence as sound and said he was confident it would be deemed admissible in court.