Authorities Investigating String of Benton County Grass Fires Get our free mobile app Since Monday, sheriff's office, Foley, Sauk Rapids and DNR fire crews have responded to seven grass fires burning in road ditches throughout Benton County. Sheriff Troy Heck says the number and frequency of the fires, along with evidence at the scene makes them believe some or all of the fires have been intentionally set. The following fires are under investigation: - March 29th at about 11:30 AM a grass fire was reported in the 2000 block of 55th St NE in Minden Township - March 30th at about 9:25 AM a grass fire was reported in the 4700 block of 25th Ave NE in Minden Township