The Independent Office for Police Conduct (IOPC) is investigating the conduct of seven officers involved in the stop and search of a man who later died.
Robert Evans, 59, was found dead at his home, in the Vauxhall area of Liverpool, on Sunday 3 July.
Merseyside Police referred the incident to the IOPC due to the fact officers had contact with Mr Evans prior to his death.
Mr Evans had been detained by officers on Eldon Street several days earlier on 28 June.
The cause of death is yet to be established and is being treated as unexplained.
As part of the independent investigation, the IOPC has conducted door-to-door enquiries and reviewed footage of the incident.
Based on the information available at this stage, the IOPC has informed six officers they are being investigated for potential gross misconduct.
The IOPC has further notified them they are under criminal investigation for potential assault offences in relation to their use of force on Mr Evans. This does not necessarily mean conduct proceedings or criminal charges will follow and the status of each officer will remain under review throughout the investigation.
The IOPC also notified a seventh officer they are being investigated for potential misconduct.
IOPC Regional Director Catherine Bates said, “We are independent of the police and our investigation will be thorough to ensure we understand the circumstances of Mr Evans’ interaction with officers on 28 June.
“Upon conclusion of the investigation, we will decide whether any disciplinary proceedings, or referral to the Crown Prosecution Service, are required.
“Our thoughts are with his family and loved ones, and all those affected, at this sad time.”