DETECTIVES are trying to trace two crucial witnesses one month on from a sex attack which left an 18-year-old woman "traumatised". 

Police have so far drawn a blank with their investigation into an attack in Chorley Old Road on June 4. 

The sexual assault was reported after an incident at 9.30pm at the junction with Conway Avenue. 

The 18-year-old was walking to the shops when she was approached from behind by a man who initially exposed himself before sexually assaulting her.

The man then walked off towards Brighton Avenue.

Detectives want to hear from two people who may who witnessed the attack and potentially may have crucial information.

One of those is described as a white man in his 50s, bald and of a large build. The other is a woman with blonde hair.

Officers have reissued an evofit of the man responsible for this attack. He is described as a white man, around 5ft 8in to 5ft 10in tall, with short mousey blonde hair.

He spoke with a thick Bolton accent and was wearing a dark grey, loose-fitting hoody, dark, loose-fitting denim jeans and dark trainers.

Police have also stressed they are not linking this to a sexual assault that happened on St Georges Road at 5.15am that morning.

Detective Chief Inspector Colin Larkin said: "It has been about a month since this young woman was left extremely traumatised at the hands of this man.

"We are continuing our efforts to find this man and arrest him, and on the four week anniversary of the crime I am once again asking the public to help us.

"We have reissued the evofit of the man responsible and I would ask that people look very carefully. If you recognise this man, then please call us immediately.

"I also want to hear from two potentially very important witnesses whom we believe could have crucial information.

"I want to stress to these two individuals that they are not in any trouble, but we believe they might have seen what happened and as such could be crucial to us finding this man.

"If you are one of these two people, or you are someone else with information then please call us."

Anyone with information is asked to call police on 0161 856 1911 or the independent charity Crimestoppers, anonymously, on 0800 555 111.