SAN DIEGO -- A man who used an AirSoft gun to steal the pain reliever OxyContin from a North Park pharmacy on three separate occasions pleaded guilty Tuesday to robbery charges.

Derek Denega, 26, will be sentenced to three years in state prison at a Nov. 4 hearing in front of Judge Michael Smyth.

Denega entered his plea to a pair of robbery counts and admitted a dangerous weapon allegation.

Prosecutors said Denega entered the Walgreens store in the 3200 block of University Avenue on May 26, July 21 and Aug. 10 and told the clerk to hand over all of the OxyContin in stock.

Surveillance cameras captured images of the thief -- a slim man clad in a hooded jacket with the head covered up or a long-sleeved pullover shirt and a white baseball cap.

On Aug. 14, a patrol officer who had seen the photos spotted Denega in the 4400 block of Ohio Street, four blocks from the drugstore, and arrested him without incident.