Knight, 66, is suspected of killing his wife, Sara Lee Knight, earlier this month.
According to a release, law enforcement officials in Maine have received several reported sightings of Knight in the state since Jan. 16. It was unclear where in the state he was spotted.
The sheriff’s department says there have been reports of Knight being spotted in several Midwestern states as well, but those could not be confirmed by local law enforcement agencies.
Knight is 6 feet 4 inches, tall, 245 pounds with hazel eyes. Officials believe he may be driving a light green 2009 Subaru Forrester with Michigan plate GM74A.
U.S. Marshals say Knight should be considered armed and dangerous. The sheriff’s department is still asking anyone with information on his whereabouts to call them at (269) 673-0500.