DETECTIVES believe a woman passer-by could hold the key to uncovering the identity of a possible sex attacker in Darwen.

Police are hoping to speak to a woman who may have seen an attack on a 12-year-old girl in the Avondale Road area of the town.

The incident happened in a back alley leading to Durham Road and police believe the attack could have been of a sexual nature.

The 12-year-old, who was not seriously injured, had been walking home from school at 4pm on Monday when a man jumped out and grabbed her.

Police refused to release full details of the attack on the girl but said they wanted to speak to a woman who walked by and disturbed the attacker.

Det Sgt Chris Counsell, of Darwen CID, said: "This was an assault on a young girl which could possibly have been of a sexual nature.

"The man had been hiding behind a white van parked near the alleyway and he jumped out and grabbed hold of her. In trying to get away from him she banged her head on the van and suffered an abrasion."

The attacker was described as male, in his late 20s, 6ft, average build, with black hair which was short but full on top with shaved sides. He was wearing sunglasses and black leather gloves, as well as a black tight fitting top possibly a fleece.

Sunnyhurst ward councillor, David Smith, said: "It's normally very quiet in that area as far as trouble goes. I've never had any complaints about anything in Avondale Road. It's a nice place and it will come as a shock to people living up there."

Anyone with information should contact Darwen CID on 01254 353841.