CCTV images have been released by police following a sexual assault in Preston.
Detectives want to speak to the man in the images after the assault on a 22-year-old woman who was walking home after a night out.
The incident took place between 2.50am and 3.10am on Monday, September 26.
Police said as the woman continued on Adelphi Street and Plungington Road, talking on her mobile phone, a man approached her from behind.
The offender put his arm around her waist before the female shrugged him off and stopped to allow him to pass.
While outside the Wellfield Pub, the same man returned before sexually assaulting her.
He was disturbed by a taxi driver before making off from the area.
The woman returned home before reporting the offence to police.
The suspect is described as Asian, in his mid-30s, of chubby build wearing a black top and trousers.
Detectives are appealing for information following the incident and are keen to speak this man, pictured, in connection with the investigation.
Det Con Richard Clancy, of Preston CID, said: “This was a particularly shocking assault which left the victim very shaken and upset.
“The male involved is believed to have followed the woman from the city centre as she returned home following a night out. Despite several clear attempts to stop the man, he has assaulted her.
“We are particularly keen to trace the male pictured and are asking anyone who recognises him to contact police.
“Furthermore, we would like to speak to a taxi driver, parked nearby, who we believe witnessed the incident, as well as another male walking in the area at the time.”
Anyone with information can contact police on 101 quoting crime reference SA1612845.
Alternatively Crimestoppers can be contacted anonymously on 0800 555 111 or online at crimestoppers-uk.org.