A lawyer for Kathie Durst’s sisters isn’t entitled to investigative information into their sibling’s 36-year-old suspected murder.

Robert Abrams, the lawyer for the sisters of Robert Durst’s first wife, sued the NYPD for case information he says shows an ex-cop private investigator colluded with police to cover up the billionaire’s role in his wife’s 1984 death.

The NYPD said disclosing the materials could jeopardize an ongoing investigation into the case that got a fresh lead in 2017.

Manhattan Supreme Court Justice Verna Saunders agreed with the NYPD.

Saunders said that since Durst was arrested by LA police in 2015 for the 2000 murder of pal Susan Berman — for allegedly knowing his role in Kathie’s death — “it is not unreasonable to believe the NYPD’s case is still active.”

Kathie’s sisters are suing Durst civilly.