A British police officer has been questioned on suspicion of manslaughter over the death of a man in protests during the London G20 summit earlier this month.
Britain's police watchdog said a second post-mortem has found that newspaper seller Ian Tomlinson, 47, who was caught up in protests on 1 April, had not died from a heart attack as first thought.
Video footage taken by a New York Fund manager showed Mr Tomlinson, who had not taken part in the demonstrations, being shoved to the ground by a police officer in riot gear. He collapsed shortly afterwards in a nearby street.
The officer involved has already been suspended by London's Metropolitan Police and the matter is being investigated by the Independent Police Complaints Commission (IPCC).
In a statement, the commission said that, following the initial results of the second post mortem, a Metropolitan Police Officer has been interviewed under caution for the offence of manslaughter.
The first post mortem had recorded that Mr Tomlinson had died from natural causes. But lawyers for Mr Tomlinson's family said on Friday a second pathology report had indicated that the cause of death was abdominal haemorrhage.
The commission has received 145 complaints about the policing of the protests which turned increasingly violent as the day wore on, with confrontations between anti-capitalist demonstrators and environmental campaigners and riot officers.
On Wednesday, a sergeant was suspended after more video footage showed him apparently lashing out at a woman who was remonstrating with him during one protest.
The capital's police chief has expressed his concern about the video images and has ordered a review of public order tactics, especially the use of "kettling" where protesters are herded by officers into a confined space.
That followed growing criticism from politicians and civil rights groups that the police had used excessively violent force to deal with the protests.