BAY CITY, Mich., (AP) — Federal prosecutors say a 76-year-old northern Michigan man has pleaded guilty to leaving two pipe bombs outside cellphone stores in Cheboygan and Sault Ste. Marie.

John Douglas Allen of Whittemore entered the plea Monday in federal court in Bay City. He faces up to 20 years in prison when he is sentenced. That’s scheduled for Nov. 9.

Prosecutors say Allen admitted that last Sept. 15, he placed pipe bombs containing shrapnel outside an AT&T store in Sault Ste. Marie and outside a Verizon store in Cheboygan. Both pipe bombs contained a note demanding $5 million.

Video footage taken from the stores captured his actions.