BOSTON — A judge on Tuesday agreed to postpone the double murder trial of former New England Patriots player Aaron Hernandez while prosecutors try to get their hands on evidence now held by a law firm that previously represented him.

The trial in the 2012 killings of two Boston men was scheduled to begin Dec. 1. Judge Jeffrey Locke moved the start date to Jan. 19.

Former New England Patriots NFL football player Aaron Hernandez attends a pretrial court hearing in Fall River, Mass. on Wednesday, Oct. 9, 2013. Hernandez was indicted in August in the killing of 27-year-old Odin Lloyd, a semi-professional football player from Boston who was dating the sister of Hernandez's girlfriend. He has pleaded not guilty. (AP Photo/Brian Snyder, Pool)

Neither side nor the judge would say what that evidence is. But Locke did say it relates to a defendant’s right to seek confidential legal advice from a lawyer.

A law enforcement official close to the investigation told The Associated Press that the issue centers on whether prosecutors should be allowed to have access to Hernandez’s cellphone.

Hernandez was convicted this year in the killing of Odin Lloyd, who was dating the sister of Hernandez’s fiancee. He is serving a life sentence.