MIDDLESEX CENTRE, ONT. -- A man who sustained a gunshot wound in London's Greenway Park on Monday has died, Ontario's Special Investigations Unit (SIU) says.

London police were called to the park around 10:30 a.m. for a 24-year-old man reported to be in distress.

Officers located the man, who was in possession of a firearm, and attempts to negotiate with him were unsuccessful, according to the SIU.

Shortly afterward, he suffered a gunshot wound and was taken to hospital with life-threatening injuries.

The SIU now says he died in hospital on Tuesday and a post mortem was completed on Friday afternoon.

Based on a preliminary investigation, the SIU says it does not appear that any officer discharged a firearm.

The SIU investigation continues, and one subject and 16 witnesses have been designated.