PHOENIX (AP) -- Authorities have arrested a suspect in the death of a 70-year-old homeless man, who was punched outside a Phoenix convenience store. Phoenix police said Monday that 30-year-old Joseph Nicholas Aguilera is being held on suspicion of second-degree murder. His bond was set at $500,000. Police say Aguilera allegedly struck the man at a bus stop near the convenience store on July 11 for unknown reasons. They say Aguilera fled the scene and was captured on surveillance video. Police say Aguilera was arrested on Friday after being identified with help from the public. It's unclear if he has a lawyer yet. The name of the homeless man hasn't been released. Police say he had been in extremely critical condition from his injuries and died on July 14.