The San Diego Police Department has released surveillance video in an attempt to catch the man seen beating a woman in the Gaslamp Quarter on Monday.In the disturbing video, a man is seen punching a woman in the face two times as she falls to the ground.The altercation happened at 8:30 p.m. on Monday near the intersection of 6th Avenue and E Street in the busy downtown area.SDPD said the 50-year-old man was arguing with his fiancée when a woman approached them to intervene.That's when the suspect swung at the woman, striking her in the face with his right hand.The man took off before SDPD arrived. His fiancée stayed at the scene but refused to cooperate with investigators, police said.