Mobile phone footage shows the moment teenager Coral Millerchip began kicking and hitting an 80-year-old man in Coventry city centre.
The video shows the man try to defend himself against the attack, but she kicks him and pushes him to the floor as friends cheer her on.
The man later died in hospital.
Millerchip, aged 19, was today jailed for a total of 44 months.
More top news
Wind and rain spreading to all parts. Drier later.
Wet and rather windy for a time today. Brighter later.
A 10-week-old puppy who was abandoned in a box by the roadside has found a new home.