The son of the man who died during the G20 protests demanded answers after footage emerged of an officer shoving his father to the ground.
In video footage obtained by British newspaper the Guardian, Ian Tomlinson is seen walking with his back to a group of police with his hands in his pockets when the helmeted officer lunges at him from behind.
The 47-year-old falls heavily to the floor. He remonstrates with the officers before being helped to his feet by passers-by.
The footage was filmed during the protests outside the Bank of England last Wednesday and is believed to show the last image of Mr Tomlinson alive.
Moments later he collapsed to the ground and died of a heart attack.
After watching the footage, Mr Tomlinson’s son, Paul King, 26, said his father left work selling the Evening Standard at Monument Station at about 7pm.
He was trying to make his way home but police at a number of barricades were not allowing people through.
He said the video showed police did have contact with his father.
But he told the Guardian: “Whether that was a cause to his death we are not to know.”
He added: “We want answers: why? Ian clearly had his arms in his pockets and back towards the police. There is no need for them to step in towards him. It clearly shows that Ian did have an altercation. Now we can say, yes he did. Up until now it has been ’if’. But now we’ve seen it, we want answers.”
The family want investigators to interview the officer who pushed Mr Tomlinson to the ground and other officers who were close by.
The death is being investigated by the Independent Police Complaints Commission (IPCC).
The footage was reportedly shot by a fund manager from New York who was in London on business.
The man, who has not been named, said: “The primary reason for me coming forward is that it was clear the family were not getting any answers.”
The newspaper said the video would be handed to the police complaints watchdog as part of a “dossier of evidence” which also includes a collection of witness statements and photographs in the aftermath of the alleged attack.
Other witnesses reportedly saw Mr Tomlinson hit with batons and thrown to the floor even before the footage was taken.
The footage shows Mr Tomlinson walking away from a group of police officers, some in riot gear and some with dogs.
As he walks he does not appear to speak to any officers or offer any resistance.
When the footage is slowed down, an officer wearing a helmet can be seen apparently hitting Mr Tomlinson from behind with a baton on the leg.
The same officer then uses both hands to shove Mr Tomlinson in the back.
None of the officers appears to offer him any help.
Mr Tomlinson collapsed shortly afterwards. A post-mortem examination revealed he died of a heart attack.
On the night of the incident police claimed protesters threw bottles and other debris towards them as they tried to help him. But protesters disputed this.