A man required three operations to his hand after being bitten in an assault.
The 20-year-old was attacked between 11pm and 11.45pm on September 18, on a recreational field between Waverly Terrace and Ventnor Avenue in Hartlepool.
Two suspects attacked the victim. One of them knocked him to the ground and the other attacked him, "viciously biting" his hand, police have said.
After seeking hospital treatment, the man needed three operations on his hand.
PC Andrew Plant, investigating officer, said: “This is a cowardly and callous attack on a young man who has subsequently had to undergo three operations.
"Anyone who may have information regarding the incident or those responsible is asked to contact police on 101.”
Contact PC Plant on 101 if you have any information or if you witnessed the incident. You can also call Crimestoppers anonymously on 0800 555 111.