SAN RAFAEL, Calif. -- Marin County District Attorney Ed Berberian said Thursday there is no evidence of criminal conduct by San Anselmo police in the fatal shooting of a man at an assisted-living facility in December.

Daniel Frederickson, 29, died after being shot by police on Dec. 16 at a home at 49 Sunnyside Ave. in San Anselmo run by Buckelew Programs.

Berberian said the two officers involved appeared to have acted appropriately.

"All the evidence indicates that both Sergeant (Marcus) Hartley and Corporal (Ryan) Dunnigan acted with great restraint in their attempt to de-escalate the rapidly unfolding, volatile confrontation with Daniel Frederickson," Berberian said.

Berberian said one minute and 45 seconds elapsed between the time the officers arrived at the home and the report of shots fired.

"The officers were necessarily required to think and act quickly when faced with a life-threatening situation," Berberian said. "The officers involved acted reasonably in self-defense of their lives. Their actions were clearly legally justified."

Berberian said his office interviewed 22 civilian witnesses and members of the San Anselmo Police Department, and reviewed dispatch tapes, transcripts, autopsy reports and other evidence as part of the investigation.

Frederickson suffered from schizophrenia but was off his medication at the time of the shooting, according to testimony at an inquest by the Marin County coroner's office. He was shot once in the torso and died at the scene.

San Anselmo police had been called to the home at the request of Frederickson's caseworker. Police said Frederickson had a knife and that Dunnigan initially tried to stop him with a Taser but that Frederickson kept advancing on the officers. Hartley then shot Frederickson once in the chest.

In a statement Thursday, police said Hartley was forced to shoot Frederickson "in defense of not only the officers' lives but those of the surrounding public including nearby elementary school children."

The home is located near Wade Thomas Elementary School.

Buckelew Programs provides support services including housing and employment for nearly 1,000 people with mental illness in the North Bay. The nonprofit organization announced the day after the shooting it would vacate the San Anselmo facility.