Barrow CID are investigating an alleged sexual assault on a 28-year-old local man, reported shortly before 3:30am on Sunday 10 June.
The incident is believed to have occurred in the rear alleyway of Cavendish Street and Scott Street a short time earlier.
A Cumbria Police spokesman said: “A forensic scene was put in place which has since been released following examination.
“The victim was uninjured but left in a state of shock, he is receiving support and being updated by specially trained officers.”
Investigating Officer, DC John Reed is seeking to identify and speak to a male and female seen in the alley at about the time of the assault.
Anyone with information is asked to contact 101 or Crimestoppers on 0800 555 111.