A 17-year-old girl was approached from behind by a man as she was walking along the canal path from Westagate at 4pm on Tuesday, May 26.
As she was entering the steps adjacent to Cooper Street, the man subjected her to a violent assault before touching her inappropriately.
The victim kicked the man off before running off to get help and the offender made off back towards the canal path.
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The victim was left with numerous cuts and bruises and severe swelling to her face and shoulder, according to police.
A 20-year-old man from Burnley has today (May 28) been arrested on suspicion of sexual assault following a media appeal.
They are currently in custody where they will be questioned by officers.
Det Sgt Sarah Hargreaves, of Burnley Police, said: "While we have made an arrest I must stress our enquiries are very much on-going and I would continue to urge anyone with information to come forward.
"This was an extremely distressing ordeal for the girl involved and we remain determined to find the person responsible but we need the public’s help.
"We do recognise the concern this has caused in the community and we have extra patrols in the area for reassurance. Anybody with concerns is welcome to speak to those officers."
The victim believes a member of the public may have appeared and walked nearby at the time of the attack, scaring off the offender.
Police are continuing to urge anybody with information about the assault – including the member of the public who may have appeared on the scene – to get in touch with them as soon as possible.
Anybody with information is asked to contact police by calling 101, quoting log number 1208 of May 26.
Alternatively, independent charity Crimestoppers can be contacted on 0800 555 111 or online at crimestoppers-uk.org.
READ MORE: Teenage girl sexually assaulted by man in 'violent' attack in Burnley