Detectives are now investigating after a man was left covered in blood after being slashed across the back.
Derbyshire Constabulary is appealing for mobile phone footage from anyone who may have witnessed and recorded the incident on Saturday.
Officers received a call from East Midlands Ambulance Service at 1.15am.
The assault is understood to have happened outside of The Association bar in Nottingham Road, Ripley.
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Detective Sergeant Sean Grainger, who is leading the investigation said: “We are aware that there were a number of people in the area at the time of this incident and understand that some of them may have been recording it on their phones.
“I’d urge anyone with such footage to send it to police, as soon as possible, as this will assist us with our enquiries.
“We are still working to establish the exact cause of the victim’s injuries, but given the nature of them what we can say is that it’s clear some form of sharp object was used during the incident.
“Thankfully the victim’s injuries are not deemed to be life-changing or life-threatening and following treatment at hospital yesterday morning he was discharged a few hours later.
“Once again, I’d like to reiterate, if you do have video of the incident or witnessed what happened, please do get in contact.”
The attacker is described as a man in his twenties, of slim build and with a shaved head. He was wearing blue jeans and a red t-shirt.
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