Sheffield Tourette's bus passenger in hammer attack
A man with Tourette's syndrome was hit repeatedly around the head with a hammer in a "cowardly" attack police believe may be linked to his condition.
Jonathan Mars, 27, suffered a fractured skull and nose and severe bruising after he was set upon as he got off a bus in Lowedges Road, Sheffield.
South Yorkshire Police said it was investigating links between the assault and Mr Mars' Tourette's.
Mr Mars said he was left feeling "terrified" after last month's attack.
Police said Mr Mars was assaulted by a man at around 22.20 BST on 4 June, but have only just released details of the incident.
Supt Colin McFarlane said: "Jonathan is a vulnerable person. He has suffered a nasty attack and one of the things we are pursuing is that it was a result of his Tourette's.
"[His attacker is] a violent person who has picked on someone with a disproportionate amount of force that could not be justified.
"I think they are a coward in what they have done and I'm determined that my officers will do all they can to ensure he gets arrested."
Describing the attack, Mr Mars, a fund-raiser for Tourettes Action, said he was "instantly knocked out" by a hammer blow after getting off the bus.
When he regained consciousness he said he had dragged himself to his flat to phone the police and ambulance service.
He said he also believes the attack may be linked to his condition.
"There was a woman on [the bus] that took offence to my Tourette's Syndrome," he said.
"I told her I had Tourette's and that's it; she got off the bus, but it is still no reason for anybody to attack me.
"It has left me terrified. I was actually scared of buses."
Police said Mr Mars' assailant got out of a silver car behind the bus before the attack and left in same vehicle.
Witnesses have been asked to contact South Yorkshire Police or Crimestoppers.