A woman was bitten and punched in an attack in a busy shopping street in Hove.
The 25-year-old victim was grabbed around the face and arms before being bitten on the face and then punched.
A man living near by intervened and Sussex Police said that detectives want to speak to the man.
A spokesman for the force said that the victim knew the man who attacked her in George Street, Hove.
Detective Constable Phil Xavier said: “We are offering support to the victim following this shocking assault.
“I am keen to speak to a man who came out of a house in Seafield Road and intervened.
“George Street is a busy shopping area and I am keen to speak to anyone who was in the area at the time of the assault.”
The attack happened at about 5pm last Tuesday (2 August).
Anyone with information is asked to contact Sussex Police on 0845 6070999 or the independent charity Crimestoppers anonymously on 0800 555111.