A Connecticut judge ruled on Tuesday that the police must release recordings of the 911 calls made from Sandy Hook Elementary School during the shooting last year that left 20 children and six adults dead.

Rejecting the state’s attempt to keep the content of the tapes confidential, the judge, Eliot D. Prescott of the Superior Court in New Britain, ruled that there was no legal basis to keep the tapes secret and found that their release would help the public assess the response by law enforcement.

“In fact,” Judge Prescott wrote, “public analysis of the recordings may serve to vindicate and support the professionalism and bravery of first responders” on Dec. 14, 2012, the day of the attack.

He ordered that the recordings be released on Dec. 4, giving the state time to appeal the ruling.

Stephen J. Sedensky III, the state’s attorney in Danbury, who fought to keep the tapes private, said he was reviewing the ruling and had not yet decided whether the state would mount a challenge.