The Special Investigations Unit has opened an investigation in the region.
A 59-year-old died in Thunder Bay on Saturday after being arrested by the provincial police.
On September 11, officers were sent to a business in Pickle Lake.
While dealing with a situation on site, officers noticed that someone behind them required medical attention.
Medical services assessed and cleared the individual before officers arrested them.
At the detachment, the man went into medical distress again and was sent to Thunder Bay.
The SIU has assigned one forensic investigator and two other investigators to the case.