OCEANSIDE — A desperate mother dropped her toddler out a second-story window into a neighbor’s arms and a police officer helped drag two unconscious people to safety when a fire raced through an Oceanside apartment late Tuesday.

Six people, including the officer, were injured in the blaze that filled an 8-unit apartment building on Waring Road with smoke, authorities said.

Investigators said a discarded cigarette appears to have sparked the fire.

Seven-year police veteran Officer Brannon Heathman dragged one elderly, unconscious victim out of the building, and a neighbor, Johnny Alvarez, helped rescue another, police said.

“It’s a little bit more than the call of duty,” police Lt. Leonard Cosby said Wednesday.

One tenant awoke to smoke in her second-floor unit in the Briarcrest apartment building, near Tri-City Medical Center, about 10:20 p.m. Tuesday. She grabbed her 3-year-old son and tried to run out of her bedroom, but the thick, black smoke barred her way, Oceanside fire Battalion Chief Terry Collis said.

She opened a window and screamed for help. Alvarez, a neighbor from an adjoining unit, said he heard her screams.

“I came outside and (saw) a lady hanging from a window with her son,” Alvarez told a journalist at the scene Tuesday night.

Alvarez said he urged the mother to drop the child into his arms. She did, and then scrambled out the window with his help.

“She said she had more people in there. Me and my neighbor and my dad, we broke down the door and went looking for them,” Alvarez said.

Another neighbor, Jose Colon, said he saw the men kick in the door and enter the heavy smoke.

Heathman then arrived and also entered the building after learning people were trapped inside, police said.

The unit was filled with smoke but the officer’s flashlight revealed an elderly person lying on the floor. Heathman and Alvarez dragged out that victim.

Nearly overcome with smoke, Heathman handed his flashlight to Alvarez, who re-entered the apartment and spotted a second elderly victim on the floor. The officer went back inside and they dragged out the second person, police said.

“They put their lives in danger doing that,” Colon said. “Thank God there’s people like that around, because if it wasn’t for them, it could have been worse.”

Oceanside firefighters arrived and helped with the rescue. Both unconscious victims were airlifted in critical condition to UC San Diego Medical Center burn unit.

The mother, child, police officer and a fourth person were taken to Tri-City Medical Center, treated for smoke inhalation and released.

Firefighters requested additional crews from Vista Fire Department and had the blaze under control in about 35 minutes, Collis said.

The fire didn’t spread past the apartment where it started, but the heavy smoke spread to other units and temporarily displaced several residents. The Red Cross was called in to assist them.

“It could have been a lot worse as far as fire damage,” Collis told reporters.

Battalion Chief Bill Kogerman said Wednesday that the investigator found that the fire was started by a cigarette left on a couch.