Seattle (CNN) -- A suspect in the attempted bombing of a Martin Luther King Jr. Day parade frequently posted his beliefs on white supremacist websites, according to the Southern Poverty Law Center, which monitors hate groups.
According to the Law Center, in 2004 Kevin Harpham posted, "I can't wait till the day I snap," on the Vanguard News Network online forums, a white supremacist site.
"Who was the person during WW2 that said something like (sic). Those who say you can't win a war by bombing have never tried," another posting purportedly by Harpham read, according to the Law Center.
On the Vanguard website, which advertises itself as "No Jews. Just Right," Harpham posted over 1,000 comments, according to the Law Center.
Although the posts did not carry Harpham's name directly, Law Center officials said they had come to know him by his writing, and recognized his work as it appeared on line.
"He'd been on our radar screen for some years," said Mark Potok, director of the Southern Poverty Law Center's Intelligence Project. "He wasn't a major character but we were aware of him."
Harpham was arrested Wednesday outside his home in Addy, Washington, about 55 miles from Spokane, where on January 17 a bomb was found along the route of the city's Martin Luther King Jr. Day parade.
A bomb squad rendered the device inert. Officials called the situation an instance "of domestic terrorism" that could have caused "mass casualties."
An official briefed by law enforcement but not allowed to speak to the media regarding the investigation said the bomb was "chilling" in its sophistication. The bomb contained anti-coagulant chemical agents intended to make anyone wounded by the blast "bleed out," the official said.
The bomb was surrounded by metal shrapnel and designed to go off by remote control, the official said.
Roger Peven, a court-appointed attorney for Harpham, said he had no comment on the internet postings and had not decided on a plea for his client, who, he said, is unemployed. "It's too early," he said, "We are awaiting to see what the grand jury does."
A grand jury is expected to hear evidence in the case on March 22, the day before the next court hearing is set for Harpham.
He has been charged with the attempted use of a weapon of mass destruction and possession of an unregistered explosive device. A conviction for attempted use of a weapon of mass destruction carries a maximum penalty of life imprisonment and a $250,000 fine, according to prosecutors.
The attempted bombing was an unwelcome reminder for many residents of the region's past with white supremacist and neo-Nazi groups.
"It was called 'the Northwest imperative,'" said the Southern Poverty Law Center's Potok, "It was a call to other white supremacists to move to the Pacific Northwest and populate the area with their own people. A nation within a nation. As ludicrous as that sounds, hundreds of white supremacists moved to the area and many still remain to this day."
Many of the postings the Southern Poverty Law Center cited Harpham as writing on white supremacist websites were written under the pseudonym "Joe Snuffy," military slang for a low-ranking soldier.
Harpham served in the U.S. Army at Fort Lewis from June 1996 to February 1999 as a fire-support specialist in the 1st Battalion, 37th Field Artillery Regiment, according to a release from Joint Base Lewis-McChord.
"He would have had to fire rounds down range," base spokesman Joseph Piek said. "That's a long way to allegedly making bombs."
But postings that the Southern Poverty Law Center said Harpham authored alluded to his Army service.
"This could be a long story but to make it short I went in the army in 96' and learned that n----- were an entirely different critter than I had thought they were," said a 2007 post by "Joe Snuffy," posted on the Vanguard site. "I realized I was at war and didn't even know it."