Police are investigating a stabbing outside a Vons grocery store in Clairemont.
It happened just after 8 on Friday night near the corner of Balboa and Genessee.
A 22-year-old man was held for about an hour for shoplifting. The security guard took the handcuffs off the suspect, who then stabbed the guard in the shoulder and arm multiple times with an unknown object before getting away, police said.
The victim was taken to Sharp hospital with life threatening injuries, but is in stable condition.
Police launched their helicopter and were searching the area for the suspect.