The police officer who initially restrained a man whose death sparked violent street protests is being investigated for gross misconduct, the police watchdog has said.
Rashan Charles, 20, died on July 22 having earlier been apprehended by Metropolitan Police officers after running into a shop in Dalston, east London.
The Independent Police Complaints Commission (IPCC) is investigating his death, and said "the officer may have breached the police standards of professional behaviour regarding the detention and restraint of Rashan as well as how he dealt with Rashan's medical emergency".
Its investigators have formally notified the officer who initially restrained Mr Charles that he is being investigated for gross misconduct.
Night of violence in east London after death
IPCC commissioner Cindy Butts said: "The IPCC investigation into the circumstances surrounding the death of Rashan Charles in Hackney on 22 July has entered a new phase.
"IPCC investigators have formally notified the officer who initially restrained Rashan that he is being investigated for gross misconduct.
"The officer may have breached the police standards of professional behaviour regarding the detention and restraint of Rashan as well as how he dealt with Rashan's medical emergency."
Ms Butts said investigators have analysed the CCTV and body worn video evidence gathered and considered the officer's detailed statement as well as statements from other witnesses to the incident.
"While this move indicates a new phase in our investigation, it does not necessarily mean misconduct proceedings will follow," she added. "We will keep the position under review as the investigation progresses."
The IPCC previously said it had found that after Mr Rashan was detained, attempts were made to remove an object from his mouth or throat.
It was later revealed that a package removed from his throat contained a mixture of caffeine and paracetamol.
Protest after death of Rashan Charles
The opening into his inquest last month heard that there had been two post-mortem examinations carried out on the unemployed man, who lived in south west London - the second on behalf of his family and the police.
But coroner's officer David Brereton said no medical cause of death has been offered, pending the results of toxicology and other tests.
A Metropolitan Police spokesman said: "It is absolutely vital that the facts of what took place are thoroughly established as quickly as possible through an independent examination of all the available evidence.
"The thoughts of the MPS are with the family of Mr Charles at this incredibly difficult time for them.
"All police officers are fully aware that they will be asked to account for their actions. No officer is above the law and they would not wish to be.
"The MPS continues to provide every possible support to the police officer and their colleagues while fully co-operating with the IPCC investigation."
The force added: "The MPS will now be reviewing what restrictions, if any, should be placed on the officer. In reaching that decision the MPS will liaise with the IPCC, as is usual.
"Day in day out, the MPS expects its officers to deal with challenging and high-risk situations as they police London. This is part of the job of being a police officer, and as an organisation it is the role of the MPS to provide support to its staff as they do their job."
Mr Charles's family have previously expressed concerns over the "openness and transparency" of the IPCC investigation into his death.
A full inquest is expected to be held in front of a jury next June.