Surveillance video shows an 81-year-old man getting knocked down, but police say say he got up and chased his attackers away.
Police say the victim was minding his own business when suddenly a suspect comes into the video frame and sucker punches the man in the back of the head.
The man falls onto the pavement in between two cars parked on the curb.
They say the elderly man suffered pain and bruising on his face and went to Lincoln Hospital in stable condition after chasing his attacker.
Police have release another clip they say is a head on shot of the suspect walking along the sidewalk with another person.
The suspect is shown in the video on the left, with a flashing sign lighting his face before running off.
Police are asking for the publics help in finding the man who threw the punch.