Two police officers are under criminal investigation over the fatal tasering of ex Aston Villa footballer Dalian Atkinson, the Independent Police Complaints Commission (IPCC) said.
The 48-year-old died 90 minutes after a West Mercia Police officer Tasered the former sportsman in the street where he grew up in Telford, Shropshire, in the early hours of Monday.
The IPCC said the two officers are also being served with gross misconduct notices.
Mr Atkinson had threatened to kill his father in a "manic state" shortly before he died, his family said.
A relative of retired football star Dalian Atkinson said he had a "weak heart" and claimed police would not have Tasered him if they had known his medical history.
Meanwhile a post mortem examination carried out on Wednesday into the cause of his death was inconclusive, the IPCC added.
IPCC Commissioner Derrick Campbell said: “Having carefully considered the evidence gathered so far, we are undertaking a criminal investigation into the circumstances surrounding Mr Atkinson’s death and the level and type of force used. Two police officers will be interviewed under criminal caution by IPCC investigators.
“As this is a criminal investigation, the IPCC is limited in the amount of information which can be released into the public domain. I would ask people to be patient during the progress of our investigation and not to add to speculation about the circumstances of Mr Atkinson’s death. Speculation across the media as a whole can risk prejudice to the investigation process.
“We will keep Mr Atkinson’s family updated and our thoughts remain with all of those affected by his death.”