Merseyside Police received a report a 16-year-old girl was raped after a man forced his way into a toilet cubicle at OMG bar on Victoria Street.
The girl reportedly went to the toilet on Monday, April 3, but the door was unlocked by the suspect who then sexually assaulted her.
Merseyside Police confirmed a 24-year-old man had been arrested on suspicion of rape in connection with the incident.
The suspect is said to have left the cubicle before the girl, who was highly distressed, was assisted by an unknown woman in the venue.
Extensive CCTV and witness enquiries have been conducted, and detectives have issued the images of a man they believe could assist in their investigation.
Merseyside Police are also appealing for the woman who helped the victim of the alleged rape to get in touch as soon as possible.
Detective Inspector Leanne Toole said: ‘This was an absolute abhorrent attack on a vulnerable teenage girl, and I would like to reassure the public that incidents such as this are rare, and we are working hard to hard to identify the offender and bring him to justice.
‘I am appealing to the man featured in this image, or anyone who recognises him to come forward as we believe he could hold information that could be vital to our continuing enquiries.
‘I am also urging for the woman who helped the victim in the toilet cubicle to contact us as soon possible as she may have some vital information in relation to the investigation.
Det Insp Toole added: ‘Providing support to victims of sexual assault has never been more important, and I would encourage anyone experiencing this to report it to us and we will support you every way we can.
‘If anyone who has suffered a sexual offence and you can find the courage to come forward and speak to us, we will deal with you sensitively and make sure that reports are thoroughly investigated.’
Anyone who witnessed the incident or who has information which could help the force with its inquiries, is asked to DM @MerPolCC, message Merseyside Police Contact Centre on Facebook or Crimestoppers on 0800 555 111 with reference 23000285218.