An 18-year-old man was taken to hospital to be treated for a serious head injury after a fight outside a Manchester nightclub in the early hours of Sunday morning.
Video footage taken at the scene and shared on social media appears to show the man being attached by security men outside the Factory nightclub in the City Centre.
An investigation has been launched and officers are appealing for anyone with video footage to get in touch.
Chief Inspector Cherie Buttle of GMP’s City of Manchester Division, said: “We’re aware that there are a number of videos circulating on social media and I cannot stress how important it is that those with footage make contact with us.
“With a mobile phone at everyone’s fingertips, filming something is often the first thing people think to do but please, pass this onto us to so we can fully investigate this matter.
“While it was early in the morning, this happened on a busy street so there may have been people who have seen something but have not yet been in touch with us.
“You can talk directly to our investigation team or pass on any information through Crimestoppers.”