It happened just after 10 p.m. Friday last night outside a strip mall on Lincoln Avenue.
Police say Andrew Isaiah Godinez, a 24-year-old transient from the area, attacked and killed Joseph Paul Gomez, 46, a Tustin resident. Gomez was working at the site as a security guard.
They say the attack was unprovoked.
The victim died later at the hospital and the suspect was arrested near the scene.
Investigators now seeking anyone who may know the suspect. Anyone with information is asked to call Anaheim detectives at (714)321-3669.