LONG BEACH, Calif. >> A gunman opened fire on a party killing three people and wounding nine at a home in the Southern California city of Long Beach, authorities said today.

Police said a man in dark clothing with his face concealed fired the shots from an alley behind the home Tuesday night on the gathering of 25 to 30 people, including a group of co-workers, before fleeing in a vehicle.

Police Chief Robert Luna said officers found a horrific, blood-filled scene when they reached the home. Seven women and two men were sent to hospitals, and three men were killed in the attack.

“I don’t believe this was just a random act of violence,” Luna told reporters this morning. “It sounds like, based on what we know at this point — again, it’s early on — this may have been a targeted attack.”

Authorities said they don’t know a motive for the attack and are searching for at least one suspect, possibly more. Luna said there’s no evidence the shooting is gang-related.

Luna said police heard partygoers were gathered for various occasions, including Halloween, a birthday and an office party. He said some of the victims worked together but declined to say where.

Luna called the shooter a coward and urged residents to come forward with any information that might lead to an arrest. He said he doesn’t remember a case with such a large number of victims in the coastal city of 470,000 people in his more than three decades working there.

“We need to solve this case,” he said. “We need to get these dangerous people off the street.”