A 20-year-old man has died after being chased by police and detained in a shop.
An officer pursued Rashan Charles on foot after attempting to stop a car in Kingsland Road, east London, at 1.45am on Saturday, according to the Metropolitan Police.
Scotland Yard said after entering the shop, he was seen "trying to swallow an object" and was then taken ill.
Mr Charles died in hospital around an hour later.
Footage apparently showing the incident has been posted on social media together with the hashtag #JusticeForRash.
An investigation has been launched by the Independent Police Complaints Commission (IPCC).
It said it had obtained evidence "which indicates an object was removed from his throat at the scene".
CCTV from inside the shop and police body worn video has also been gathered and viewed.
Chief Superintendent Simon Laurence, borough commander for Hackney, urged people to keep up-to-date with information from the Independent Police Complaints Commission (IPCC) amid concern over "speculation" about how the man died.
Mr Laurence said: "In the early hours of Saturday officers attempted to stop a car on Kingsland Road, E8.
"A man, who was in the car, was pursued on foot before entering a shop where he was seen to be trying to swallow an object. He was then taken ill.
"He was taken to hospital by the London Ambulance Service where, sadly, he died later that morning. Our thoughts remain with his family and friends.
"The Independent Police Complaints Commission (IPCC) has launched an independent investigation to establish what happened and has viewed the officers' body worn video.
"There is likely to be speculation over the next few days regarding what led to this man becoming ill, so I would encourage people to keep up-to-date with the IPCC's statements, as and when they are released.
"All police officers are fully aware that they will be asked to account for their actions - officers are not exempt from the law and we would not wish to be."
IPCC investigators are keen to speak to any witnesses who were in the Kingsland Road/Middleton Road area of Hackney at the time.
Anyone with information should contact them by emailing firstname.lastname@example.org.