A “joint intelligence bulletin” issued on the day federal agents raided the Colville-area home of Kevin W. Harpham suggests that the bomb may have included a rocket motor igniter and was made in such a way to focus shrapnel at a specific target.
The bomb consisted of a steel pipe with a hole drilled at its base.
“The pipe was welded to a roughly cut steel plate,” according to the report, which was posted to a research Web site Wednesday.
The explosive charge was described as black powder, which was contained in a plastic bag.
“While not yet confirmed, the initiator appears similar to a rocket motor igniter,” the report states. “An RMI was used in a crude IED carried by a lone individual who took hostages and threatened employees in the Discovery Channel Building” in Silver Spring, Ma., on Sept. 1, 2010.