SPOKANE, Wash. >> The bomb was sophisticated and potentially deadly, but it did not detonate. No one was hurt, and no one has been arrested. So Spokane became a mystery.

“To me, it’s that God’s gracious hand moved,” said Chief Anne Kirkpatrick of the Spokane Police Department. “This was a bomb of significance that would have caused devastation.”

Nearly a month after a cleanup crew found the live bomb along the planned route of a large downtown march honoring the Rev. Martin Luther King Jr., the FBI is investigating the incident as an act of domestic terrorism. And Spokane has cycled from shock to relief to reassessment: Have the white supremacists who once struck such fear here in the inland Northwest returned at a new level of dangerousness and sophistication?

“We don’t have that kind of intelligence level to make that kind of explosive,” said Shaun Winkler, a Pennsylvania native who recently returned to the region to start a landscaping company and a chapter of the Ku Klux Klan.

Winkler lives not far from Hayden Lake, Idaho, where he once was among the followers of Richard Butler, a white supremacist and Aryan Nations leader who spent more than two decades proclaiming the inland Northwest to be the capital of a new white homeland. Butler died in 2004 after losing the 20-acre Aryan Nation compound in a lawsuit and losing many of his followers, as well.

More than 200 white supremacists were once based at Hayden Lake, but Winkler, echoing assessments by human rights advocates, said that “only a very small handful are still around.” He said his new group had about a dozen members. Several of them recently picketed taco stands in nearby Coeur d’Alene, Idaho, and distributed racist, vulgar fliers at North Idaho College. The college now owns the Hayden Lake property and calls it a “peace park.”

“We believe in protecting ourselves, but we certainly aren’t going to advocate bombing people,” said Winkler, 32, adding that he had been interviewed by the FBI about the bomb in Spokane, about 40 miles to the southwest. “That’s a pretty extreme measure even from our end. It’s going to be more of an under-the-radar person, a lone-wolf type.”

The bomb, partly concealed by two T-shirts and stored in a Swiss Army brand backpack, was found on a bench on the King holiday, Jan. 17, by contract sanitation workers less than an hour before the planned start of the march. The march went on but was rerouted. The region’s bomb squad responded and some people were evacuated, but most people were unaware of the bomb until later in the day.

The device is being analyzed by FBI experts in Virginia. Various news reports, most citing anonymous sources, have said it contained metal pellets covered in a chemical, possibly rat poison, and that it could have been detonated remotely. Frank Harrill, an FBI spokesman in Spokane, described the bomb as “capable of killing or injuring multiple people” but would provide no further details.

Kirkpatrick said the bomb was far more dangerous than a pipe bomb found near a federal courthouse in Spokane last March. No arrests have been made in that case either.

In 1996, a pipe bomb exploded outside Spokane City Hall. No one was injured; two white supremacists were later convicted in the case.

This time, Kirkpatrick said, “It’s scary the level of the calculation that was involved.”

In the weeks since the bomb was found, investigators have asked people to check cell phone photos and video that might have been taken in the area at the time. They have also returned to the scene at the same time on a subsequent Monday, hoping to gather information from people who routinely travel the area.

“Oh, I wish, I wish I had seen something,” said Kandy Conrad, who works at Auntie’s Bookstore, directly across Washington Avenue from the bench where the bomb was found and who parked nearby that morning. “All I was thinking about was did I have to put money in the meter, because it was a holiday.”

“I’m much more aware of my surroundings now,” Conrad said.

A week before the bomb was found, the Spokane City Council approved a contract to build a new road that will be the city’s first street named for King. Previous efforts to rename existing streets were rejected. The application for the street name was submitted by Ivan Bush, the former director of the Martin Luther King Jr. Family Outreach Center in Spokane and one of the organizers of the Jan. 17 march.

Bush said he helped organize the city’s first march honoring King, in 1984.

“There were 49 of us back then, and we marched from the jailhouse to the federal courthouse,” said Bush, 60. “Now we have thousands.”

Asked whether the increase in numbers meant that Spokane had made progress, he said, “Yeah, but we need deeper progress.”

While not everyone is convinced that racism was a factor in the bomb incident — the march included many prominent elected officials who are white, including the mayor and county commissioners — Bush is among many people who find it impossible to believe that it was not.

The city should be more assertive in confronting the questions of racism stirred by the bomb, Bush said. For him, the days in the 1980s and 1990s when it was common to see white supremacists openly promoting their views feel like they were “just yesterday.”

“We’ve moved beyond those days as far as active, visible things,” Bush said. “But we need to pull the covers back and take a look at what’s underneath. I think if we did that, we would find that those sentiments are very much prevalent.”

Winkler, the Klansman, said he still believed that the region was a good place to nurture a racist movement. And as for the bomb in Spokane, he added, “Even though we wouldn’t have participated in that, it certainly wouldn’t have hurt my feelings if it did go off.”

© 2011 The New York Times Company