Police said on Monday that Shannon Miles, 30, who is accused of shooting and killing Harris County Sheriff’s Deputy Darren Goforth, has a history of mental illness, the Associated Press reports. After an arrest in 2012, he was sent to a state mental hospital for several months.

Sheriff’s Deputy Darren Goforth, 47, was fatally shot multiple times on Friday evening while filling up his patrol car at a gas station in suburban Houston, Texas. A manhunt for the suspect, who approached the uniformed Goforth from behind before shooting him, continued Saturday.