Attorneys for backpack bomber Kevin Harpham filed a motion late last month to reconsider his guilty pleas in the attempted bombing of last year's Martin Luther King Jr. Unity March in Spokane.
The motion, filed Dec. 29 in U.S. District Court, argues that Harpham should be allowed to withdraw from a plea agreement he entered last September.
In the plea, Harpham admits to attempting to "cause bodily injury to a person or persons by use of an explosive device."
A forensic expert retained by the defense argues that device planted by Harpham, described in court documents as a pipe bomb containing lead fishing weights dipped in rat poison, acts more like a shotgun than an explosive.
The expert, Frederic W. Whitehurst, also calls into question whether the device would work at all had Harpham been able to detonate it. (F.B.I. officials say Harpham was never within range of the device's remote detonator since Spokane Police rerouted the march after city workers discovered the bomb.)
The motion says that Harpham didn't have Whitehurst's report when he entered the plea and therefore "did not enter a knowing, intelligent voluntary plea," and should be allowed to back out of it.
Whitehurst, a former FBI agent and whistleblower who revealed negligence in the agency's laboratory in the early 1990s, also testified for the defense in the trial of an accomplice to Oklahoma city bomber Timothy McVeigh, according to the New York Times.
At the sentencing hearing for Harpham last month, federal defender Roger Peven argued that his client should be allowed to withdraw from his plea because of Whitehurst's report.
U.S. District Judge Justin Quackenbush denied the withdrawal of plea because Peven didn't provide Whitehurst's report to him at the hearing.
He then sentenced Harpham, who maintained his innocence, to 32 years in prison, the maximum allowable under the plea agreement.
A voicemail left on Thursday afternoon with Kimberley Deater, a trial attorney in the federal defender's office, was not returned.
Prosecutors have until Jan. 13 to respond to the motion. Assistant U.S. Attorney Tom Rice declined to comment on the motion.