Two men are facing jail after fatally attacking a homeless man in Trafalgar Square after a shift at Harrods.
Agency workers Lucas Antunes and Luis Abella were caught on CCTV as they set upon 51-year-old Desmond O’Beirne at around midnight on June 3 2017.
Mr O’Beirne had asked the pair for a cigarette and when they said no he threatened to “shank” them, it was claimed.
He was seen in video footage walking away when Antunes, 21, landed a punch to the head, sending him to the ground, and Abella, 22, appeared to kick him.
Mr O’Beirne never recovered consciousness and died from a brain injury on December 20 last year.
Earlier this year, police offered £20,000 to anyone who could help track down the culprits.
In April, O’Beirne’s sister Vivienne Folan said: ‘My brother Desmond was hard-working and larger than life.
‘He was on a night out in Trafalgar Square when he was brutally and viciously attacked by two cowards who then calmly walked away and left him for dead.”
Following the appeal, Antunes, of Tottenham, north London, was tracked down by authorities in the United States and returned to face justice in Britain.
He went on to plead guilty to manslaughter while Abella, from Lambeth, south London, admitted attempted assault occasioning actual bodily harm on Friday.
Detective Chief Inspector Noel McHugh, of Scotland Yard, said: “This is a tremendous result. We have got some justice for Desmond and his family.
“He was punched in the back of the head and kicked while he was on the ground.
“He was out on a night out and he suffered injuries which would put him in a coma for six months.
“This case shows the power of the media supporting us and the amazing public coming forward to support this prosecution.
“Without you we would not have secured a conviction.”
Mr McHugh added: “Combined with some brilliant detective work in the UK, a huge thank-you to our American partners who tracked him down and brought him back so swiftly.”
The victim, originally from Ireland, was said to have had an itinerant lifestyle and had a sister living in Wales.
Mr McHugh expressed the hope she would now be able to rebuild her life.
Abella originally faced a manslaughter charge but it changed to the lesser charge following a review.
The pair will be sentenced at the Old Bailey on February 8.
A Harrods spokesman said the defendants were not staff but were employed by Buzz Retail, which provides workers for demonstrations within Harrods, both for less than a year, in 2017.