The death of man who was taken ill on a mobility scooter during a police stop-and-search is being investigated.
Peter Howieson, 52, was detained in Blackburn on 24 March on suspicion of drugs offences, the Independent Office for Police Conduct (IOPC) said.
He was riding a mobility scooter at the time but became unwell during the search at about 10:30 GMT and died later in hospital.
The IOPC said an independent investigation had begun into his death.
IOPC regional director Amanda Rowe said: "I send my condolences to Mr Howieson's family and everyone affected by this sad event.
"In circumstances where a man has died soon after being detained by a police officer it is appropriate that we thoroughly investigate to establish what happened."
IOPC said it had taken statements from the PC and two security guards but appealed for other witnesses to come forward.