Ontario’s police watchdog says it has launched an investigation after a 44-year-old man died in police custody in Orillia.

The Special Investigation Unit says Ontario Provincial Police officers responded to a disturbance Sunday shortly after 6:45 p.m.

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The SIU says three man were arrested and taken to the OPP’s Orillia detachment and lodged into cells after being searched.

It says one of the men was found without vital signs during a routine check Monday at around 6:30 a.m.

The Special Investigation Unit says the man was pronounced dead after unsuccessful resuscitation efforts.

Three investigators and one forensic expert are assigned to examine the circumstances surrounding the death.