An individual investor in 3Com was charged Wednesday by federal authorities with threatening to bomb investment firms if they did not boost the company’s stock.

John Tompkins of Dubuque, Iowa., was charged with 15 counts, including securities fraud, intent to extort, possession of an unregistered destructive device and using a destructive device while committing a violent crime. Tompkins, a machinist, was arrested in April and accused of sending threatening letters and bombs to investment firms under the guise of “The Bishop.”

The bombs and letters were in an attempt to get the investment firms to boost the price of 3Com and Navarre stock, of which Tompkins was an investor. Tompkins reportedly sent 17 letters and two bombs to investment firms in the Midwest.

The firms did not comply with Tompkins’ demands, according to federal prosecutors.

Tompkins could face life in prison if convicted on the charge of using a destructive device while committing a violent crime.