Police have arrested a probationer who was shot and wounded by a San Diego police sergeant last week when he allegedly pulled a fake handgun on him outside a Mira Mesa strip mall after he signed himself out of the hospital where he was being treated for his wound.

Robert McBride Jr., 22, apparently walked out of Scripps Memorial Hospital La Jolla about 5:30 this afternoon, according to police. He had not been arrested for last week's incident and was allowed to leave by the hospital.

"Often time, hospitals will call and say they're going to release somebody on such and such a date. I don't know that that happened or not," said Lt. Greg Jacobs of the San Diego Police Department.

Officers fanned out through the area in search of McBride, who suffered a gunshot wound to the chest in the officer-involved shooting.

Scripps La Jolla released a statement saying that since the patient was not under arrest or assigned a police guard at his bedside he was free to sign himself out of the hospital

McBride's wife drove him from the hospital to the City Heights home of his grandparents. She did not give her name, but told reporters her husband was wheeled out of Scripps La Jolla by hospital staff. McBride's sister said Thursday's arrest was a "complete shock", adding the "real story will come out".

Shortly before 12:30 a.m. Jan. 26, McBride allegedly pulled a realistic replica pistol during a confrontation with SDPD Sgt. Robert Wills in a parking lot outside a CVS pharmacy at Camino Ruiz and Mira Mesa Boulevard. Fearing for his life, Wills, a 21-year department veteran, opened fire, according to police.

Wills had contacted McBride after seeing him and a cohort walking near a row of cars, appearing to possibly be casing them for valuables to burglarize, Lt. Kevin Rooney said.

When Wills asked for some identification, McBride started to hand over his wallet, then ran off through the parking lot.

Wills gave chase for a few moments until McBride stopped, turned around and started to run back towards the officer while also allegedly pulling out what appeared to be a handgun from his waistband and raising it, Rooney said.

The fake gun that McBride allegedly drew on Wills was indistinguishable from a real one at a distance, especially in the dark of night, according to Rooney.

Wills was not injured during the confrontation.

McBride was expected to be booked into county jail on suspicion of exhibiting an imitation firearm in a threatening manner and probation violation upon his recovery.