FRESNO, Calif. (AP) — Police in California say a detective fatally shot a man who was attacking him inside his office Tuesday at police headquarters.

Fresno Police Chief Paco Balderrama says it was not immediately clear how the man gained access to the building, which has secured gates and doors. He said the man entered the detective’s office on the first floor and assaulted him with an unknown object, cutting the officer on the neck and head. He says the officer fired at least one shot, killing the man, who has not been identified.

The officer was taken to a hospital and is expected to recover.