Maine State Police are investigating a series of automated bomb threats that caused several Wal-marts to evacuate customers and employees.

According to the Portland Press Herald, a threat was reported to Biddeford Police at 7:33 p.m. An investigation determined it was unfounded and cleared the store for re-entry at 8:22 p.m.

Similar threats were reported in Houlton, Falmouth, and Scarborough. Stores in Skowhegan, Waterville, Windham, and other communities also reported receiving the threats, as well as the Palmyra location.

Police say the bomb threats have been reported in several other states, including New York, Idaho, and Wyoming.