CHEBOYGAN, Mich. (AP) — The FBI is seeking information on two explosive devices found outside cellphone stores in northern Michigan.

The bombs, which were defused, were found in suspicious packages left outside a Verizon store in Cheboygan and an AT&T store in Sault Ste. Marie.

Cheboygan authorities say emergency personal were dispatched around 9 a.m. Thursday after an employee reported a suspicious package near the door of the business. A similar device was reported the same day in Sault St. Marie.

The FBI and Michigan State Police believe the devices are related to a series of letters discovered in the Upper Peninsula last month.