By Kristina Bravo, Mark Mester and Christina Pascucci

LONG BEACH, Calif. (KTLA) -- A shooting at a Long Beach retirement home left a fire captain dead and two other people injured early Monday, officials said.

Capt. Dave Rosa, 45, a 17-year veteran with the Long Beach Fire Department, was killed during a fire response, according to the agency.

Police have detained a person of interest and have recovered a weapon, Chief Robert Luna said.

A bomb squad was en route after two devices deemed suspicious were found, Luna said. He did not specify where the bomb squad was heading.

The Fire Department responded to a report of a fire alarm at 600 E. 4th St. at around 3:49 a.m., Long Beach Fire Department spokesman Jake Heflin said. A retirement home called Covenant Manor was listed under that address.

Officials arrived at the multistory building and discovered windows blown out and an activated sprinkler, Heflin said.

The firefighters found the fire and were able to knock it down at 3:59 a.m., but they continued to assess the area due to reports of an explosion and the smell of gasoline.

At around 4:08 a.m., Rosa and another firefighter were shot, according to the Fire Department.

The second firefighter remained in stable condition at St. Mary Medical Center in Long Beach, the agency added. That firefighter's name has not been released.

Rosa, who served as fire captain for the past 6 1/2 years, left behind a wife and two children, the Fire Department said.

"You go to these scenes and you never know what's on the other side of those doors," Luna said at a Monday morning news conference. "These brave firefighters went through those doors and unfortunately they were met with gunfire."

Police said a civilian who was shot "during the chaos" had to undergo surgery and was in critical condition.

Earlier, the Fire Department said one of the firefighters was in critical condition and the other sustained non-life-threatening injuries.

In a cellphone video a bystander provided to KTLA, a noise that sounds like a gunshot is heard while a fire alarm goes off.

Dan Rafferty, who recorded the footage, said he awoke to alarms going off and saw several firefighters and police officers in the area.

Rafferty said he heard a total of three shots fired and screaming. Rafferty said he saw a paramedic with a possible gunshot wound.

“[The paramedic was] not even on the stretcher. They just lifted him up and carried him," Rafferty said.

Gina Kim told KTLA she heard firetrucks going by and proceeded to help people from the retirement home cross the street when she heard "two loud booms."

Authorities closed down Atlantic Avenue between Fourth and Fifth streets.