A San Diego police officer shot in the head in City Heights late Saturday afternoon fights for his life while officials try to sort out the details. Police said Sunday the attacked was "unprovoked" and followed a shooting nearby by the same suspect, who was later shot and killed by other police officers.

The San Diego officer shot at about 5:30 p.m. Saturday remains in "very critical condition" Sunday at Scripps Mercy Hospital with a head wound.

San Diego police chief William Lansdowne is preparing to discuss the shootings with the media Sunday afternoon.

But a police spokesperson did say Sunday that the officer, still unidentified, was on patrol in the City Heights neighborhood in San Diego late Saturday afternoon when the suspect pulled up beside the police officer's car, pointed a shotgun out the passenger window, and fired at the officer unprovoked, striking him in the head.

Capt. Jim Collins of the San Diego police department's homicide squad said there is no indication the officer was trying to question the gunman, nor was the officer apparently aware that the man who pulled up beside him and shot him was a suspect in a shooting reported minutes earlier at a fast-food restaurant in El Cajon.

The officer is "in extremely critical condition," Collins said.

The officer was reportedly given first aid by civilians on the scene, and taken to the emergency room by paramedics.

San Diego police swarmed the area to look for the suspect after the reported shooting, finding him in an apartment building.

"The suspect grabbed the shotgun (when officers reached him) and several officers fired their weapons at him," Collins said.

The suspect was pronounced dead at the scene.

Officials have not identified the suspect, who was killed and suspect in the two shooting Saturday afternoon, including the officer and another victim at the fast food restaurant. That shooting reportedly occurred at 5:20 p.m. Saturday at an In-N-Out hamburger restaurant in unincorporated El Cajon.

The suspect also shot that victim in the face, though that victim is expected to survive.

The suspect was reportedly driving a black Audi with paper dealer license plates.

An El Cajon officer, unaware of the shooting, had seen the Audi speeding west on Interstate 8 in San Diego and chased it, but he pulled off the chase when the Audi exceeded 100 miles per hour.

Minutes later police received a radio dispatch that the officer was shot and made the connection between the Audi and the shootings.

At 6 p.m., police found a vehicle that matched the description -- a black Audi with paper plates -- on 48th Street near University Avenue in San Diego. There, officers approached the vehicle, the suspect driving the vehicle grabbed the shotgun, and police officers opened fire with multiple rounds, killing the suspect.

The Audi rolled backward into a fence, officials said, and the man inside was declared dead on the scene.