The man accused in Long Island’s infamous Gilgo Beach serial killings has lost his bid to separate the sprawling case involving seven victims into multiple trials.

Judge Timothy Mazzei ruled Tuesday that the trial against Rex Heuermann, a Manhattan architect who lived on Long Island, would move forward as a single trial. In his six-page ruling, he sided with prosecutors who argued that the killings were committed in a similar matter and that evidence in the cases overlaps.

“We wanted one and that’s what we got,” Suffolk County District Attorney Ray Tierney said after the brief hearing in Riverhead court.

Michael Brown, Heuermann’s attorney, said he was disappointed but accepted the judge’s decision.

Heuermann was arrested more than two years ago and has pleaded not guilty in the deaths of seven women dating back to 1993. Remains of most of the victims were found on an isolated stretch of a shoreline parkway not far from Heuermann’s home, authorities say.

Lawyers for Heuermann had argued in court filings that there was no “unique and consistent modus operandi” common to all the killings, as prosecutors claimed. They said the case should be broken up into as many as five trials because the killings involved different time frames, torture and mutilation techniques, and dump sites for the bodies.

Heuermann’s lawyers also contended that jurors would struggle with the “volume and complexity” of the evidence in the case if all seven killings were tried together. They argued the 62-year-old Massapequa resident risked being improperly convicted by the “cumulative effect” of the evidence against him.

Prosecutors, in their own filings, dismissed variances in the alleged killing styles as “minor inconsistencies” that showed Heuermann was either “refining and tinkering” with his methods, or intentionally trying to “confuse or mislead law enforcement” — an argument that the defense rejected as “untenable.”

They noted the victims were all petite women in their 20s involved in the sex trade and that the remains of nearly all of them were found in the same location.

Prosecutors also maintained that many of the victims are connected by overlapping evidence and witnesses, making a single trial a “judicious and efficient use of time and taxpayer resources.”

On other matters, Mazzei on Tuesday turned down defense lawyers’ second attempt to toss out some of the DNA evidence that prosecutors say overwhelmingly implicates Heuermann.

Heuermann’s lawyers had argued that DNA evidence developed by Astrea Forensics violated state public health law because the California lab does not hold a required permit from New York’s health department to handle lab specimens.

But Mazzei sided with prosecutors, who said in their court filings that the state health law cited by defense lawyers applies only to certain clinical labs — not ones used in criminal investigations.

Tuesday’s rulings were the latest decisions in the case, which still doesn’t have a trial date.

Mazzei ruled earlier this month that prosecutors could use Astrea Forensic’s findings in the forthcoming murder trial, marking the first time advanced DNA analysis has been allowed as evidence in a New York court.

Heuermann’s next court appearance is scheduled for January.