According to a statement by Leicestershire Police, landlord Christopher Shields, of Hockley Farm Road in Braunstone, had been involved in an argument outside his pub, the King Richard III in Highcross Street, Leicester, with 52-year-old David Cooley on a Sunday night in May last year.
Shields, 55, appeared at Leicester Crown Court where, after a trial lasting 10 days, he was convicted.
Terence Stevenson of Norfolk Way, Leicester, was a customer in the pub that night and pleaded guilty at an earlier hearing to perverting the course of justice after CCTV footage capturing the events of the night was deleted, police said.
Senior investigating officer, Detective Chief Inspector Martin Smalley, who led the investigation, said: “Extensive enquiries were carried out by officers in the area that included trawling through hours of CCTV footage and speaking to witnesses as we tried to piece together the exact circumstances surrounding the incident.”
Leicestershire Police said the court heard how shortly after midnight on Monday 23 May, Shields punched Cooley, causing him to fall to the pavement and hit his head on the kerb.
The police statement read: "After landing the punch, Shields walked back inside the pub and spoke to 47-year-old Stevenson who could be clearly seen tampering with the CCTV equipment when specialist officers recovered the deleted footage.
"A member of the public called the ambulance service and David, from Dersingham Road in Leicester, was taken to the Leicester Royal Infirmary for treatment. He was later conveyed to Nottingham’s Queen’s Medical Centre where he died three days later on 26 May."
A post-mortem examination determined Cooley died as a result of a head injury, said the police.
Smalley continued: “David died as a result of tragic circumstances and the events of that night will continue to haunt many people for many years to come.
“His family remain devastated by his death and I can only hope that today’s verdict will go some way towards helping them to move forward.
“David was enjoying a regular evening out with friends and couldn’t possibly have conceived what was to happen later that night.
“The outcome of this case should act as a warning to anyone intent on causing injury to another person. One punch is all it took to end one man’s life and change the lives of others forever.”
Shields and Stevenson will be sentenced at a later date.