A 20-year-old man has died after being chased by police and apprehended in a shop.
A Metropolitan Police officer pursued the man on foot after they attempted to stop a car in Kingsland Road, east London, at 1.45am on Saturday, the force said.
The man went into a shop where he was seen "trying to swallow an object", Scotland Yard said.
A force spokesman said: "The man entered a shop in Kingsland Road, where he was seen to be trying to swallow an object.
"The officer intervened and sought to prevent the man from harming himself, but he was then taken ill."
London Ambulance Service attended, and before they arrived first aid was provided by officers, including a police medic.
The man was then taken to an east London hospital, where he was pronounced dead around an hour later.
His next of kin have been informed. A post-mortem examination and formal identification are to take place.
The Independent Police Complaints Commission is investigating the incident, and the Directorate of Professional Standards has also been informed.
The IPCC said it had launched an independent investigation at 3.10am on Saturday - less than an hour and a half after police pursued the man.
It said it had obtained evidence "which indicates an object was removed from his throat at the scene".
He was taken to the Royal London Hospital where he died.
CCTV footage from inside the shop and police body worn video has also been gathered and viewed.
Investigators are keen to speak to any witnesses who were in the Kingsland Road/ Middleton Road area of Hackney.
Anyone with information should contact investigators by emailing witness_contact@ipcc.gsi.gov.uk.