The Independent Police Complaints Commission (IPCC) is to investigate claims that a man was battered by the police in his own home.
Stephen Whenary, 36, says he was beaten by officers who were called to a domestic dispute at his Stockton home in August 2005.
He was charged with assaulting police and resisting arrest, but cleared at Teesside Magistrates' Court on 5 May.
Cleveland Police Chief Constable Sean Price referred the case to the IPCC.
On the final day of the hearing, Mr Whenary was cleared by a judge who said the police evidence was 'riddled with discrepancies'.
The court heard how one officer could not attend the hearing because he had gone on holiday, while another could not produce his notebook detailing the incident because it had been destroyed in the wash.
A spokesman for Cleveland Police Authority, which has backed Mr Price's decision, said: "We welcome the chief constable's approach to this particular case, especially as he himself has seen items within that case that have brought grave concerns.
"We are delighted we have a forward-thinking chief constable who hides away from nothing."
Mr Whenary's solicitor, Lee Goodchild, of Taylor Goodchild, in Middlesbrough, said: "We are aware that Cleveland Police have approached the IPCC to carry out an investigation as well as the internal investigation by police.
"We will wait and see with interest what findings the IPCC return following its investigation."