A federal judge scolded the defense lawyer for accused Hanukkah-party slasher Grafton Thomas on Monday after suggesting he tipped off reporters to a sealed hearing in the case last month.

Judge Cathy Seibel read aloud a portion of the transcript of the Jan. 3 closed-door proceeding at which, she said, lawyer Michael Sussman told her that journalists had gathered outside her courtroom in White Plains.

“I wonder what drew them here this afternoon,” Seibel said, quoting herself.

“I wonder, too,” she said, quoting Sussman.

Seibel then told Sussman that she believed he’d been at best “playing dumb” and at worst “lying” to her.

She also said the lawyer had a “duty of candor” to the court, adding, “I trust that this won’t happen again.”

“Yes, your honor,” he said.

Also during Monday’s hearing, Seibel gave Sussman until Wednesday, and prosecutors until Thursday, to propose redactions to the transcript before it’s released to the public.

The Post has filed a motion to have the transcript unsealed, arguing that the criminal case against Thomas — who’s charged with federal hate crimes for allegedly wielding a machete against five Orthodox Jews celebrating Hanukkah in Rockland County on Dec. 28 — is a matter of “intense public interest.”

The Jan. 3 hearing involved a motion by Sussman to quash a prosecution subpoena for evidence he removed from Thomas’ Greenwood Lake home and a cabin where Thomas, 37, formerly lived in Wurtsboro.

Thomas, who Sussman claims is mentally ill and unfit to stand trial, wore an orange jail jumpsuit and sat silently in court during Monday’s proceedings.

Sussman wouldn’t answer questions afterward.