CALGARY -- The province's police watchdog is asking for the public's help for details on what happened to a man who died while in custody of the Calgary Police Service Monday.

The Alberta Serious Incident Response Team (ASIRT) was called to investigate the circumstances of the death of a 43-year-old man who went into medical distress during an incident involving police officers at 6 a.m. on April 6.

An early investigation shows emergency medical services (EMS) were dispatched to a location in southwest Calgary to assist a man believed to be suffering from a mental health issue.

When paramedics arrived, the man ignored their commands. A second EMS unit, as well as Calgary police officers were called to the scene.

While the man was being escorted to the ambulance, an incident occurred and police handcuffed him.

Once handcuffed, the man was carried to the ambulance by EMS and, when he was inside, paramedics discovered he had stopped breathing.

Paramedics administered CPR on the man while on the way to hospital, where he was later pronounced dead.

ASIRT is investigating and request that anyone who was in the area of the 2400 block of Erlton Road S.W. at the time of the incident contact them at 403-592-4306.