Parked at a truck stop in Southern California in early July, a Brink’s truck had it all: gold, gemstones, Rolex watches — and a guard, sound asleep. Thieves broke into the truck and made off with 22 bags of the jewelry, according to two lawsuits.

The owners of jewelry say they lost tens of millions of dollars in the heist, and law enforcement officials are searching for the thieves. In the meantime, the armored-truck company and the jewelry owners are arguing in dueling lawsuits about how much money Brink’s must repay.