The province's Special Investigations Unit has been brought into an investigation in Melanchton Township.
Police haven't released a lot of details, but Dufferin County OPP say they were called to a domestic incident around 10pm last night at a residence on the 2nd Line.
Dundalk fire also responded to a call about a fire at the same location at 8am this morning.
The SIU was notified earlier today and has invoked its mandate.
The 2nd Line Melanchton between 240 Sideroad and Dufferin County Rd. 21 remains closed this afternoon.