A girl with learning difficulties has been sexually assaulted in a Bolton library.
The 14-year-old was sitting at a computer in High Street library in Deane at 1730 BST on 5 July, when she was attacked by a man from behind.
He was seen by staff, who confronted him, but he fled with another man.
Police said the victim's mother spotted the attacker again two days later outside Sunning Hill School in Deane and confronted him, but he ran off.
Det Con Adam Gleave said: "This must have been a very disturbing incident for the victim who is not only young, but has learning difficulties.
"She has been seen by specially trained officers and we have reassured both her and her family that we are confident of catching this man.
"We believe this man lives in the Deane area because, on the day he was confronted by the mother, it was raining very heavily and he was not wearing a jacket.
"We therefore think he was probably close to home or work.
"Also, when the attack happened in the library, he was with another man who may or may not have seen what happened.
"There is no suggestion that he has done anything wrong, so I would also appeal for him to pick up the phone and tell us what he knows.
"His friend carried out a disturbing attack on a young girl in a public place and we would really appreciate him getting in touch."
The attacker is described as Asian, aged in his late teens, wearing silver glasses with thick metal frames, a long-sleeved white shirt with thin pinstripes and dark trousers.