Investigators were still searching for a suspect or suspects after three men were killed and nine other people were taken to hospitals after a shooting Tuesday night at a costume party at a home in the Southern California city of Long Beach, fire officials said.

Officials said those injured were seven females and two males ranging in age from 20-49. They warned the number of wounded people could rise because they didn’t know if people at the party had brought themselves to the hospital.

Five of the injured people were considered “immediate,” or with injuries that paramedics believe could potentially be life-threatening, said Long Beach Fire Department public information officer Jake Heflin.

“It looks like it was a party, some type of a Halloween-type costume party and that seems to be where the shooting occurred,” Helfin said, according to video from NBC Los Angeles.

Long Beach Police Chief Robert G. Luna added Wednesday morning that the costume party was a Halloween, birthday hybrid, and it appears that the 25-30 people who were there when the shooting happened worked together somewhere outside of Long Beach.

Firefighters responded to the shooting at Seventh Street near Temple Avenue at about 10:45 p.m.

Helfin said the shooting took place at a residence behind a storefront, and the three men who were pronounced deceased were discovered in the backyard. Luna said the scene was “horrific,” adding there was “blood everywhere.”

He said Wednesday morning that witnesses said a male suspect fled in a dark-colored vehicle. Investigators don’t know if other people were involved, and have not determined a motive, but believe the party was targeted.

Luna said the gunman fired “almost indiscriminately, not caring who he hits.”

“We’re just very anxious to find out why would somebody do something like this. This is not reflective of our community of Long Beach — this does not happen here,” Luna said, adding that he has been with the department for more than 30 years and cannot remember an incident with a dozen victims.

“I know people have information as to who this coward is. I would like them to come forward,” Luna said.

A man in the neighborhood told reporters that just before the violence, he was on his way to a liquor store in the area, which he said was normally quiet. The store was closed, and he was walking home when he said he heard around 20 shots and ran.

“It didn’t seem real. I thought I was dreaming,” he said. “It was continuous shots,” he added.

Long Beach is a city on the southern tip of Los Angeles County.