Police have released an e-fit of a suspect they want to speak to after a man was punched to the ground, then attacked by a dog in Rotherham.
The 39-year-old victim confronted three men on Kilnhurst Business Park on Glass House Lane on 5 August.
They repeatedly punched him and then encouraged a dog to attack him while he was on the ground.
The man received serious injuries, including a broken jaw and bite wounds. Police said the attack was "horrific".
Officers have urged anyone with information to come forward.
The men were at the back of a business premises, with one on top of an electricity sub-station, when they were confronted by the victim at about 1900 BST.
Police said nearby workers came to the man's rescue after hearing his screams.
He spent several days in Doncaster Royal Infirmary and needed surgery for his injuries.
Det Con Iain Martin, of South Yorkshire Police, said: "This was a horrific attack and could have been much worse for the victim had staff not intervened when they did.
"We are continuing to investigate the incident and hope that the e-fit will prompt people to get in touch with police."
The gang fled in the direction of Rawmarsh after the attack.
The dog is believed to be a Staffordshire or pitbull terrier type.