Aaron Muggleton, 25, formerly of Alexandra Street, even stole his victim's credit card as he lay unconscious on the floor.
Today Muggleton was found guilty of murdering 39-year-old Simon Mushonga after a two-week trial at Northampton Crown Court.
Simon, from Bedford was out celebrating his birthday with friends in the early hours of December 8 last year when Muggleton attacked him in Carrington Street, completely unprovoked.
He was punched three times with what prosecutor James House described as “huge force”, causing him to fall to the ground, crack his head on the pavement, and lose consciousness.
While he lay there unconscious, Muggleton stole a credit card from Simon before making off.
He was arrested a short time later by police and subsequently charged with grievous bodily harm.
Simon was rushed to hospital, but never regained consciousness and died a short time later. Muggleton’s charge was then upped to murder and today he was not only found guilty of that but also of stealing from Simon while he lay unconscious, of assaulting Simon’s friend on the same night and of assaulting another man outside Abacus nightclub on November 17, 2018.
Detective Inspector Stuart Hitchon from Northamptonshire Police’s Major Crime Team, said: “Simon Mushonga was by all accounts, a very nice man who was reserved, polite and well-meaning.
“This was a completely unprovoked attack on an innocent man which has left a family devastated. Simon was not a confrontational man – he simply wanted a quiet night out to celebrate his birthday.
“His killer, Aaron Muggleton, can expect to receive a lengthy sentence behind bars and I hope he uses this time to reflect on the consequences his mindless violence has had. Not only did he kill Simon but he has also been found guilty of two other unprovoked assaults.
“Finally I would like to commend Simon’s family and friends for the way they have conducted themselves during this trial. I hope the result today brings them some comfort, though nothing can truly take away the pain they feel in a world without Simon.”
Muggleton is due to be sentenced at Northampton Crown Court on Tuesday, July 2.
A 16-year-old girl who cannot be named for legal reasons was originally charged with manslaughter but the case was dropped.