Officers found Nicholas K. Oates, 25, sitting at the beach in Venice Saturday night and arrested him without incident.
They say Oates was at the mall Friday when he took some books off the shelves of a store and lit them on fire. When a store employee tried to stop him, Oates allegedly pulled out a gun and pointed it at the employee.
The store and eventually the entire shopping mall were evacuated.
In the chaos, there were also concerns about a suspicious package found at the scene, but it was determined to be harmless.
The next day police found what they believed to be the suspect's vehicle at the mall. They impounded it and were able to identify Oates as the suspect. A flyer was distributed and officers spotted him at Venice Beach around 8 p.m. Saturday.
Police are still searching for the gun.
Anyone with information is asked to call LAPD Major Crimes Division at (213)486-7260 or 1-877-ASK-LAPD. Anonymous tips can be provided to Crime Stoppers at (800)222-TIPS.