"Significant questions" remain about the behaviour of a police officer cleared of the manslaughter of Ian Tomlinson during the G20 protests, the police watchdog has said.
The Independent Police Complaints Commission's deputy chairwoman, Deborah Glass, ordered that Pc Simon Harwood will now face Metropolitan Police disciplinary proceedings in public.
Mr Harwood, 45, was acquitted at Southwark Crown Court of the manslaughter of Mr Tomlinson in the City of London in April 2009. A jury of seven women and five men took 18 hours and 45 minutes to clear him.
He cried in the dock and his wife Helen sobbed as the verdicts were given, before they tearfully embraced as he was freed. Mr Tomlinson's family also broke down, while outside court stepson Paul King called the verdict "a joke" and vowed to pursue the issue in the civil courts.
Mr Harwood hit 47-year-old Mr Tomlinson with a baton and pushed him to the ground on the fringes of the G20 protests. The father-of-nine walked 75 yards before he collapsed, and died later in hospital from internal injuries.
It can now be reported that Mr Harwood faced a string of allegations about his behaviour before he came across Mr Tomlinson.
Ms Glass said it was "staggering" that he managed to medically retire from the Met while facing disciplinary proceedings for an alleged road rage incident - and despite this was later re-employed by the force as a police officer specialising in public order.
She said: "While the jury has today acquitted Pc Simon Harwood of manslaughter, it is clear that significant questions remain in connection with his actions on the day Ian Tomlinson died.
"Whether or not those actions were reasonable will be tested further at a misconduct hearing in September, which I have directed will be held in public. There are also questions in this case that the Metropolitan Police Service must answer."
Mr Harwood, from Carshalton in Surrey, said he used reasonable force when he hit Mr Tomlinson with a baton and shoved him to the ground as he walked away from police lines in the City of London. An inquest into Mr Tomlinson's death was held last year, when the jury returned a verdict of unlawful killing.