Manitoba’s police watchdog is investigating the death of a man who died in custody of Winnipeg police.

The Independent Investigations Unit say officers responded to report of a disturbance near the CN rail line in east Winnipeg just before 4 a.m. last Thursday.

Police told the IIU a 41-year-old man became unresponsive as he was being handcuffed.

He received medical attention and was taken to hospital, where he was pronounced dead the next day.

The cause of death is still unknown, said the IIU.

Witnesses or anyone with information is asked to contact the IIU, which investigates all serious incidents involving police officers in Manitoba.