Kevin William Harpham, an unemployed electrician from Colville, Washington, pleaded guilty in September to attempting to use of a weapon of mass destruction and attempting to commit a federal hate crime.
Federal prosecutors have recommended that Harpham, who is in his 30s, be sentenced to 32 years in prison, according to court documents. He is scheduled to learn his fate Tuesday in a Washington state courtroom.
The plea agreement signed by Harpham described him as a white supremacist and said he wanted to hurt people at the MLK Day parade earlier this year "to further his racist beliefs."
The backpack containing the device was discovered, and no one was injured. But law enforcement officials said that if Harpham had succeeded, many people could have been harmed. Harpham had packed a 6-inch steel pipe with 100 grams of black powder and more than 100 fishing weights, which were intended to be shrapnel.
In addition, Harpham coated the weights with an anticoagulant. According to court documents, he intended to set off his bomb using a transmitter and receiver from a remote car starter device.
The plea agreement says Harpham's DNA was matched to the backpack; investigators tracked his purchase of the fishing weights to a local Walmart store and an Internet buy of the remote triggering mechanism; and they retrieved a camera from his home that contained pictures Harpham had taken of himself at the march.