BUFFALO, Minn. (AP) - Authorities say a tip from an ex-wife pointed them to a Sartell man suspected in a string of armed robberies along Interstate 94 from the St. Cloud area to the Minneapolis suburbs.

Police released a security video after a masked man robbed a Burger King in Maple Grove Wednesday. The ex-wife of 34-year-old Douglas Wayne Gravelle saw the video on the news and told police he wore the same clothes at a child support hearing. She said he's addicted to prescription drugs and unemployed.

Gravelle is being held in the Wright County jail on charges of aggravated robbery and kidnapping.

Police say some items seized at his home tie him to the robberies. His bail was set Friday at $500,000. More charges are expected at his next court appearance Tuesday.