Two teenage members of a "happy slapping" gang have pleaded guilty to killing a pensioner in front of his granddaughter in south London.
Ekram Haque, 67, a retired care worker, was attacked in August 2009 in Church Lane, Tooting, as he left a mosque.
He died a week later from injuries which included a wound to the head.
The boys, aged 15 and 16, pleaded guilty to manslaughter at the Old Bailey. Another 15-year-old youth admitted causing actual bodily harm.
None of the boys can be named because of their age.
So-called "happy slapping" attacks refer to violence which is recorded by the perpetrators on mobile phones.
The attack on Mr Haque on 31 August was witnessed by his three-year-old granddaughter.
The boys were charged with his murder but the lesser charges of manslaughter and assault occasioning actual bodily harm were accepted by prosecutors.
CCTV cameras in the area caught two boys striking Mr Haque from the front and back while a third boy was seen running off with them. The pensioner fell to the ground and suffered a head injury.
Brian Altman QC, prosecuting, said: "There was evidence available to us to from mobile telephones of so-called 'happy slap' type activity in the week leading up to these events."
All three teenagers also pleaded guilty to causing grievous bodily harm to two other men, Atta-ul Hassan Mir and Imdad Bukari, on the same day as the attack on Mr Haque, as they too left the mosque during the Muslim festival of Ramadan.
Two of the boys also admitted causing actual bodily harm to a couple in their 70s, days before the fatal assault.
Jasumati and Jushbhai Patel were punched and stamped on in their home after they asked the boys not to sit on their wall, the court heard.
The court heard that the teenagers were in a gang which called themselves Lane Gang Productions.
During the investigation officers found six videos of "happy slapping" incidents on mobile phones belonging to the gang, but the attacks the youths were charged over were not among them.
All three will be sentenced on 23 July.