SAN DIEGO (AP) — A shootout at an apartment left a police officer and two other people dead Thursday, sending dozens of residents running from their homes, many in their pajamas.

Officer Christopher Wilson was fatally shot in the confrontation that began Wednesday night, when San Diego County officers and U.S. marshals went to check on a man on probation and serve an arrest warrant on another.

After the man on probation slammed the door in their faces, officers pushed their way into the apartment and arrested him, said Assistant Police Chief Jim Collins. Four other people ran into a back bedroom, including the man police believe was named on the warrant, he said.

Officers got backup from the San Diego police department and then kicked in the door of the bedroom, where they were met with gunfire, Collins said.

Wilson, a 17-year police force veteran, was fatally shot in the living room while three officers fired back. Two officers fled to another bedroom and eventually escaped out a window, Collins said.

Fellow officers carried Wilson down the stairs from the second-story apartment. Moments later, police banged on residents’ doors, yelling, “Get out! Get out!” witnesses said.

A 26-year-old father of two who only identified himself as Luis listened to the confrontation from his downstairs apartment. “I just heard like a big boom, then they exchanged some words, then I heard, ‘Officer down! Officer down!'” Luis said.

He told The Associated Press that he looked out his window and saw officers carrying Wilson, whose face was covered in blood. Luis yelled for his wife and two young children, and was preparing to make an escape when officers banged on his door to help his family leave safely.

“It was pretty scary,” said Luis, who fled without putting on his shoes.

Luis said his family joined about 50 men, women and children who were running, crouched down, to the other side of the complex, under the crackle of gunfire. Some were in pajamas and slippers.

They later made their way to a supermarket parking lot across the street, where they spent the night as the standoff continued until shortly after dawn.

After a SWAT team tossed a nondestructive grenade to make a loud noise and flash of light inside the apartment, a man and woman inside notified police that they wanted to come out. They were detained for questioning, Collins said.

An hour later, police shot tear gas into the apartment.

When no one else emerged after 90 minutes, police crept back into the apartment, Collins said, where officers discovered a man and woman fatally shot on the floor, which was littered with guns. Police believe the dead man may be the suspect named on the warrant for a case of assault with a deadly weapon.

It was not immediately clear whether the two committed suicide or died during the shootout, Collins said. He also did not know how many weapons were found in the home.

Police have not released the suspects’ names or details about them, saying they were investigating. Police said they believe the man on probation may have been harboring the man wanted on the warrant, but they did not know the relationship between them and the others in the apartment.

Wilson, 50, who had served in the Navy, patrolled the southeast working class neighborhood called Skyline for years. He helped train rookies and taught them to treat residents respectfully, city officials said.

He died early Thursday at a San Diego hospital, where his family said goodbye to him, officials said.

“Every mayor and police chief dreads a day like today,” said San Diego Mayor Jerry Sanders at a news conference. He said Wilson, who had a 17-year-old son and 20-year-old daughter, “was popular, funny, extremely bright, and a consummate professional.”

“It was routine for other officers to pay him the compliment by calling him ‘good cover.’ In other words, you always knew Officer Wilson had your back,” said Sanders, who had to stop after becoming choked up.

Gov. Arnold Schwarzenegger said flags at the state Capitol will be flown at half-staff.

“Officer Christopher Wilson gave his all in the line of duty and dedicated his life to protecting the people of San Diego,” he said.

A police dog named Monty also was shot in the mouth but was recovering, Collins said.