A federal grand jury in Spokane has added a federal hate crime to the charges pending against Kevin William Harpham, a white supremacist suspected of planting a deadly backpack bomb along the city's Martin Luther King Jr. parade route.

A federal grand jury in Spokane has added a federal hate crime to the charges pending against Kevin William Harpham, an alleged white supremacist suspected of planting a backpack bomb along the city’s Martin Luther King Jr. Day parade route.

Harpham is named in a new four-count indictment issued late Thursday. It adds two counts, one relating to a violation of the federal Hate Crimes Act and the other accusing him of attempting to use an explosive device in connection with the hate crime. Harpham faces up to life in prison if convicted.

He had earlier pleaded not guilty to charges of attempting to use a weapon of mass destruction and knowingly possessing an improvised explosive device.

Federal Public Defender Roger Peven said late Thursday he had not seen the indictment but was aware the grand jury was considering Harpham’s case this week.

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The new charges had to be approved by Deputy Attorney General Thomas Perez, who heads the Department of Justice’s Civil Right’s Division in Washington, D.C.

The indictment alleges Harpham planted an improvised explosive device in Spokane before the parade “because of the actual or perceived race, color or national origin of participants.”

As with the previous indictment, the new grand-jury documents provide no details of the government’s case. Several news outlets, including The Seattle Times, Spokane Spokesman-Review and The Associated Press, have asked a federal judge to unseal documents that would outline the case against Harpham.

Harpham, 36, was arrested March 9 by an FBI Hostage Rescue Team near his home in the small, rural community of Addy, about 55 miles northwest of Spokane.

He’s accused of leaving a backpack containing an explosive device packed with shrapnel and rat poison on a bench along the route of the Jan. 17 parade in downtown Spokane. The backpack was found by three city sanitation workers 40 minutes before the start of the parade.

A source familiar with the investigation has said authorities linked Harpham to purchases of bomb components, including a remote car starter and other electronics. The purchases were traced to various stores, and at least one purchase was made with a debit card, the source said.

In addition, DNA recovered in the backpack or on the bomb was linked to Harpham, the source said.

Harpham was a member of the neo-Nazi National Alliance in late 2004, according to Mark Potok, director of the Southern Poverty Law Center. Potok, whose Alabama-based office tracks hate groups in the United States, said it was not known when Harpham joined or whether he was still a member.

Mike Carter: 206-464-3706 or mcarter@seattletimes.com

Information from Seattle Times archives is included in this report.