A police officer who hit Ian Tomlinson with a baton and pushed him to the ground at the G20 protests has been found not guilty of manslaughter.
PC Simon Harwood, 45, of south London, denied the manslaughter, in April 2009, of Mr Tomlinson, 47, on the grounds that he used reasonable force.
Mr Tomlinson, was pushed as he walked away from a police line in the City of London. He later collapsed and died.
His family said they would be pursuing the case in a civil court.
It is not clear if that will be against PC Harwood as an individual or against the Metropolitan Police.
"After the unlawful killing verdict at the inquest last year, we expected to hear a guilty verdict - not a not guilty verdict and it really hurts," Mr Tomlinson's stepson Paul King, said outside the court.
"It's not the end, we are not giving up for justice for Ian."
Members of Mr Tomlinson's family cried in the public gallery as the verdict was delivered at Southwark Crown Court.
PC Harwood, in the dock, and his wife, in the public gallery, also cried.
The jury of five men and seven women had considered their verdict for four days.
During the trial, the police officer had accepted he was "wrong" to have hit and pushed Mr Tomlinson.
He said had he realised at the time Mr Tomlinson was walking away from police lines, he "would not have gone near him".
Father-of-nine Mr Tomlinson, a heavy drinker who had slept rough for a number of years, walked 75 yards before he collapsed.
It has emerged that, in 2000, five years after he joined the Met, PC Harwood was involved in what was described at Mr Tomlinson's inquest as a "road rage" incident but his employment record was kept from the jury.
He was off-duty and the other driver complained of unlawful arrest and abuse of authority.
PC Harwood denied the accusation but retired on medical grounds in 2001 before a disciplinary hearing took place.
He rejoined the Met in late 2004 - Scotland Yard's vetting unit had considered the road rage incident but had not reviewed the full file.
Deborah Glass, deputy chairwoman of the Independent Police Complaints Commission, said after the verdict "significant questions" remained over PC Harwood's actions on 1 April 2009.
She said whether or not those actions were reasonable would be tested at a misconduct hearing to be held in public in September.
"PC Harwood was able to retire from the Metropolitan Police while facing disciplinary proceedings for previous alleged misconduct towards a member of the public," she said.
"That he was then re-employed by the force, first in a civilian role and later as a constable, is simply staggering and raises considerable concerns about their vetting procedures."
The Met Police, meanwhile, said it was clear "insufficient recording and checks meant detailed information regarding the officer's misconduct history was not shared at key points".
"We got that wrong," it said in a statement, adding there had since been "huge changes" to its vetting system.
"Now all applicants, including officers applying to become police staff, as well those re-joining or transferring from other police services, are formally vetted and this involves a full misconduct intelligence check."