SAN DIEGO -- Two police detectives were legally justified in opening fire on a gang member after he shot at them in a Mountain View alley, District Attorney Bonnie Dumanis' office concluded in a ruling released Tuesday.

The June 10 non-fatal shooting of 21-year-old Jeff Quijano of San Diego by SDPD Detectives Martha Gasca and Ramon Valentin "was reasonable under (the) circumstances" due to the imminent and potentially lethal threat they came under at his hands, according to the legal analysis.

Gasca, Valentin and Detective Laura Zizzo were in a parked unmarked Buick Regal, clad in street clothes for an undercover surveillance assignment, when a white van with Quijano inside approached them near 40th and Eta streets in Shelltown about 7:40 p.m.

After several of the people in the cargo vehicle made eye contact with the detectives, the driver stopped abruptly, backed up and then drove off through a nearby dirt lot. Though suspicious about the encounter, the detectives decided to remain at their post to wrap up their stakeout.

A few minutes later, they spotted the van again while heading to the north on 40th Street and called in a patrol unit to intercept it. When the driver turned right into an access road in the 3900 block of Ocean View Boulevard, the detectives followed.

By the time Valentin steered into the entrance to the alley, the van was stopped about 50 feet away and a young man was standing beside it, holding a .22-caliber pistol in a "two-handed shooting stance," according to the district attorney's analysis.

The gunman opened fire, and a bullet shattered the windshield of the detectives' unmarked car. Zizzo, who suffered a minor cut from flying debris, screamed and fell onto her side as Gasca and Valentin returned fire, discharging a total of 11 rounds. The assailant, who had fired seven shots, then got back into the van, which sped off.

The detectives gave chase and kept the van in sight until patrol vehicles and a police helicopter crew took over the pursuit. About a mile from the site of the shootout, the fleeing driver lost control of the vane, which crashed into a concrete pillar at Palm Avenue and Interstate 805.

Officers arrested Quijano, who had suffered a bullet wound to the lower body from Gasca's 9 mm handgun, and his four companions.

Police subsequently determined that the group had allegedly robbed a woman in the 3800 block of Gamma Street shortly before the exchange of gunfire with the undercover detectives.

Several of the suspects later told investigators that Quijano had pegged Gasca, Valentin and Zizzo as undercover police prior to the shooting, according to Dumanis.

Quijano, a documented gang member who was on parole at the time of the shootout, faces 15 felony counts, including three counts of attempted murder of a peace officer. He is being held on $1 million bail pending a preliminary hearing this week.

Under state law, Gasca and Valentin were entitled to use deadly force to protect themselves and Zizzo from the lethal threat posed by Quijano, according to the ruling from Dumanis' office.

"To have refrained from using deadly force could have resulted in any of the detectives suffering serious bodily injury or death," the document states.