SAN DIEGO - A San Diego police gang unit officer was killed and a second was hospitalized following a shooting late Thursday night during a traffic stop in the Southcrest neighborhood.

The events that led up to the shooting just before 11 p.m. in the 3700 block of Acacia Grove Way, near Boston Avenue, were not immediately detailed.

The reason for the attempted field stop, and whether the suspect was on foot or in a vehicle at the time, remained unclear this afternoon, according to police.

San Diego Police Chief Shelley Zimmerman initially said that shortly after the two announced they were making a stop, they requested "emergency cover" from other officers. Responding officers found both men with gunshot wounds to their upper bodies.

Residents of the 3800 block of Boston Avenue were told to shelter in place as officers searched the area for a possible second suspect.

Police identified the deceased officer as Jonathan DeGuzman, a 16-year veteran of the force. DeGuzman, 43, was married and has two children, police said.

The injured officer was identified as 9-year veteran Wade Irwin. Police said the 32-year-old Irwin is married and has a 19-month-old child.

Zimmerman said both officers were wearing body cameras and bulletproof vests. She noted that investigators were unsure if the officers were victims of an ambush.

DeGuzman was rushed to Scripps Mercy Hospital in Hillcrest in a patrol car. Following his death at the hospital, DeGuzman's body was escorted out of the hospital in a motorcade just before 6 a.m. to be taken to a funeral home.

Irwin was taken by ambulance to UC San Diego Medical Center in Hillcrest, where he underwent emergency surgery and was expected to survive.

Zimmerman said Irwin was "resting comfortably" following his surgery.

A suspect, identified as Jesse Michael Gomez, was taken into custody in a ravine area in the 1300 block of South 38th Street and was transported to UCSD Medical Center, police said. He remains hospitalized in critical condition with a gunshot wound he suffered in the confrontation.

Gomez, 52, was arrested on suspicion of murder and attempted murder, police announced Friday afternoon.

Police said another person possibly linked to the shooting holed himself up in a home in the Shelltown area. SWAT officers entered the home in the 4000 block of Epsilon St. but did not find anyone inside. Officers then turned their attention to a home on nearby 41st St., but after nearly an hour, officers left the scene.

10News learned a second man, Marcos Antonio Cassani, was taken into custody near the scene of the Epsilon St. standoff. The 41-year-old Cassani was arrested on an outstanding warrant, police said.

Cassani's connection, if any, with the shooting or Gomez was not immediately known. He was considered by police a "potential" suspect.

"At this time, we have not determined if Cassani is involved in the murder of Officer DeGuzman and the attempted murder of Officer Irwin," Zimmerman said.

Team 10 learned Cassani lives in the house on Epsilon St. that SWAT officers surrounded for most of the day.

A 10News photojournalist shot video of Cassani in the back seat of a police cruiser at SDPD headquarters vomiting into a trash can. He was later walked inside for questioning.

Team 10 pulled documents from three courthouses to get a clear picture of Cassani's background, and it turns out he has a long rap sheet.

It started in 1992, when he went to prison for two burglaries. In 2003, Cassani went to prison again for burglary. In 2004, he got 2 years for driving around in a stolen car.

There were several arrests and convictions for possession of methamphetamine, and in 2009, he was sent back to prison for carrying a concealed dagger, something parolees are not supposed to do.

DeGuzman is the 33rd SDPD officer killed in the line of duty since 1913, and the third killed by gunfire since 2010.

"I personally worked with him [DeGuzman] when I was a lieutenant at Mid-City Division," Zimmerman said. "I know him, and this is gut-wrenching. He cared. He came to work every single day just wanting to make a positive difference in the lives of our community. And last night he lost his life trying to make a positive difference and trying to protect our community."

She also lamented the uptick in violence against police officers across the country in recent weeks.

"That's just a tragic statistic of police officers that go out every single day that wear a badge with pride that we all took an oath to protect and serve all of our communities," she said. "And to have this happen to our police officers, we have seen this happen way too many times just in these last few weeks across our great country. It is tragic for everyone."

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