A backyard gathering of football fans turned into a bloodbath after gunfire broke out in Fresno, California last night.

The shooting left four people dead and six wounded, according to police. Three men were killed at the scene and a fourth died in a hospital.

Responding Fresno police officers were going door to door in the neighborhood, in hopes of collecting security camera footage or witness accounts. They were looking for leads to help them locate “unknown suspects.”

Fresno City Councilman Luis Chavez, who represents the southeast portion of the city, where the shooting occurred, called it a “senseless and criminal act.”

Investigators on the scene included officers with the Federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

The slayings in Fresno followed a recent wave of violence in California that has included the murder-suicide deaths of a family in San Diego on Saturday; the deaths of two high school students in Santa Clarita plus the shooter on Thursday; and the deaths of at least four people at a house party in Orinda on Halloween night.

Sunday’s gunfire erupted around 8 p.m., authorities said at a late-night news conference. About three dozen people were at the party and all of the victims were Asian men between ages 25 and 35, they added.

“Officers arrived on scene and what we found were several individuals deceased in the backyard,” said Lt. Bill Dooley of the Fresno Police Department. “We do have multiple shooting victims.”

“What we do know is that this was a gathering, a family and friend gathering in the backyard,” Dooley said. “Everyone was watching football this evening when unknown suspects approached the residence, snuck into the backyard and opened fire.”