The police watchdog, the IPCC, has upheld a complaint that a Cleveland Police officer punched a man.
The man in his forties was arrested at home in Hartlepool last year.
He also said police went through his mobile phone to stop him filming the incident.
The officer involved will face a misconduct meeting, and the force has been asked to look into whether the man was wrongly arrested.
More top news
Northumberland has won Silver in the Best UK Holiday Destination/County in the prestigious 2015 British Travel awards last night.
Police from five forces have carried out raids today aimed at stopping an escalating feud in the travelling community.
Newcastle United supporters have the highest number of active banning orders in the Premier League.