A man stabbed to death outside a nightclub in Manchester city centre had been jailed over his role in a fatal club attack.
Clarence Edwards was found with stab wounds following a disturbance at about 03:30 GMT on Sunday on Charles Street outside the RBase club, said police.
A 37-year-old man from Manchester has been arrested on suspicion of murder.
It is not known if the assault on Mr Edwards was a revenge attack and police said they do not yet know what sparked the trouble.
Det Supt Joanne Rawlinson, of Greater Manchester Police, said: "We know there will be speculation and rumour in the community about what happened and why, and it is important that people do not jump to conclusions or second guess what has gone on."
She said: "All we know for certain is that this young man has been killed and his family have been left devastated.
"If you know anything about the reasons why Clarence was attacked or the circumstances leading up to it, you have an absolute responsibility to him, his family and to the justice process, to do the right thing and let us know.
"We know there had been a party at RBase nightclub on Charles Street on Saturday night which was attended by a large number of people who may have vital information which could assist us with our investigation."
She said the force had a dedicated syndicate of experienced detectives investigating his death and urged any witnesses to the incident to come forward.
Mr Barrett, 31, from Harpurhey, died from a stab wound to his back at Sinclair's Bar on Drake Street in the early hours of Christmas Day.
Mr Edwards was convicted of violent disorder and sentenced to two and a half years in prison in March 2013.