According to the law enforcement oversight organization Chatham-Kent paramedics were called to the area of Victoria Ave and Grand Ave around 7pm on Tuesday.
The Chatham man was in some sort of distress and acting erratically. Police were called and the man was taken to hospital with police.
Shortly after getting to the hospital he died. His identity has not been released.
A team of five investigators has been placed on the case.
Anybody with an information is urged to call the SIU.