Bomb threats were called in yesterday to two Walmarts in Kansas—following threats to eight stores Friday in Missouri. The warnings prompted the stores to close their doors after evacuating customers, but investigators found no explosives, ABC News reports. A recorded voice in the Missouri bomb threats said: "There's a bomb in the building. You have two hours to get everybody out this store. This is not a joke," according to a local police chief, who believes all the Missouri threats are linked. Police are continuing to investigate.