MINNEAPOLIS (WCCO) – Investigators have recovered a possible clue in a jewelry heist in southern Minnesota.

Robbers escaped with more than $500,000 in diamonds, gold and silver from a van at a rest area near Rochester last week.

Employees from a jewelry company had stopped there while traveling home from a trade show.

On Friday, someone found one of the cases stolen during the heist.

There wasn’t any jewelry in it, but the state crime lab is now analyzing it.

The jewelry company put out a written statement: “This was a planned attack. We are thankful that none of our employees [was] harmed in the incident.”

The FBI is also trying to figure out who did this.