He said the man was in transit at KLIA from the UK to Phuket, Thailand, when he disrupted other travellers and started acting aggressively, leading to his arrest at 1.30pm.

“During the arrest, the detainee acted aggressively and destroyed several items belonging to the police and also caused injuries to two policemen and an auxiliary policeman,” he said in a statement.

The man was then investigated for mischief, voluntarily causing hurt and obstructing policemen from performing their duties, said Hussein.

“During the documentation process, the detainee fell unconscious. Police immediately sought medical assistance. He was given preliminary treatment by a doctor before he was confirmed dead.

“An autopsy was conducted at the Sultan Idris Shah Hospital in Serdang yesterday but the cause of death has yet to be determined pending lab results.”

Hussein said the case had been classified as sudden death.

The Independent Police Conduct Commission has been notified about this case. Bukit Aman’s integrity and standards compliance department is also probing the death.