The FBI has made an arrest in the MLK Day Spokane bombing. And the alleged culprit is–not surprisingly–a white supremacist.

An FBI source in Washington, D.C., said one man was arrested east of Spokane. Agents, including a bomb expert from Quantico, Va., were preparing to search a house where others associated with the suspect were living, the source said.

The suspects are apparently affiliated with white supremacists.

The source, who is familiar with the investigation but is not authorized to speak on the record, said that “good police work” led to the arrest and that forensic evidence taken from a backpack bomb was key to the case.

Update (not sure what happened to presser, but maybe Holder has decided not to speak publicly about terrorism since he got dinged the last time):

They’ve identified the suspect as Kevin William Harpham:

An ex-soldier with ties to the white supremacist movement has been taken into custody in connection with the planting of a backpack bomb along the planned route of the Martin Luther King Jr. march in downtown Spokane, authorities have confirmed.

Kevin William Harpham, 36, of Colville, could face life imprisonment on charges of attempted use of a weapon of mass destruction and possession of an unregistered explosive device, according to documents on file in U.S. District Court. An initial court appearance is scheduled for this afternoon.