Steven Bennett and Suni Singh Gill attacked Anthony Bird at Victoria Park, Tipton, on a Sunday morning in July last year, repeatedly kicking and punching him in front of horrified families as they falsely accused him of being a paedophile.
The father-of-five known locally as "Goughy", died in hospital 17 days later as a result of blunt force head impact, with a background of serious pre-existing liver disease which impaired his blood clotting.
On Tuesday Bennett and Gill were convicted of murder after four hours and 13 minutes of deliberation by the jury in unanimous verdicts following a trial at Wolverhampton Crown Court.
During the trial the court was told the pair did not know the victim, who had been walking through the park at the time of the attack on July 26. Bennett and Gill turned on him after a female companion told them that Mr Bird had taken a photo of her children.
A witness told the jury that Gill was the first to attack Mr Bird, followed seconds later by Bennett with continuous kicks. Despite being urged to stop, they carried on.
Mr Bird able to stagger out of the park to the home of his niece, while stunned onlookers phoned 999 to report the attack.
Bennett claimed to only punched Mr Bird once, while Gill claimed he was drunk and had mental challenges and could not recall all of what happened.
Afterwards West Midlands Police revealed that, while the attack was not caught on camera, CCTV footage did show Bennett and Gill laughing and re-enacting the brutal and prolonged assault.
Sentencing the pair on Wednesday Judge Michael Chambers QC said: "In my judgement the victim was particularly vulnerable. He was caused physical suffering. There were further aggravating circumstances
"Clearly this was a spontaneous act. I accept that.
"In your case Gill I am not satisfied that you were suffering from any mental disorder or mental disability which lowered your degree of culpability. It is right to observe that you have a history of mental heal issues and post traumatic stress.
"I accept the evidence given that this was not operative at the time of the incident. Even though you were diagnosed with post traumatic stress disorder the motivation for your actions were probably due to anger, intoxication or drugs."
"I see no reason to distinguish between the two of you and your culpability," the judge added.
Bennett, 38, of Bevan Road, and Gill, 33, of Shore Road, both Tipton, were each jailed for a minimum term of 16 years and 313 days minus time already spent in custody on remand.
As Mr Bird's killers were taken away to the cells, a member of Mr Gill's family, was heard to shout: "This isn't right".
But at the hearing Alastair MacDonald QC, prosecuting, read aloud the family's impact statement provided by the father-of-five's daughter Tania who described how she held him in her arms and "sobbed" when he passed away on August 12 last year after his condition deteriorated.
After Tuesday's conviction, Mr Bird's five adult children released a statement in which they paid tribute to their "caring and kind" father.
“We have to live with the memory of visiting our dad in hospital following the violent attack on him last summer. It was huge shock to see how badly beaten dad had been and it is a memory that we are worried will stay with us forever," they said.
“Our dad was an extremely caring and kind man. He was very proud of his children and was over the moon to be a grandfather. Sadly he never got to meet his second grandson who was born a month after he was killed.
“We will never understand why anybody would want to take our dad’s life in such a brutal manner."