A 29-year-old Watsonville man was arrested in Santa Cruz yesterday after shoplifting a bottle of alcohol from a convenience store. Christian Martinez was stopped by a security guard after attempting to steal the alcohol, but when the guard detained him, Martinez fought to escape. When a witness stepped in to help the security guard, Martinez pulled out a switch blade and stabbed the witness in the forearm. Martinez ran away, but was found during an area search by officers a short while later. He was taken into custody on charges of brandishing a weapon and assault with a deadly weapon. The stabbing victim was transported to Dominican Hospital with non-life threatening injuries.