Why isn't this a hate crime instead of dom terrorism? Is everything terrorism now? SEATTLE (Reuters) The FBI is treating the investigation of an unexploded backpack bomb left along the parade route of a Martin Luther King Jr. holiday celebration as a possible case of domestic terrorism, an agency spokesman said on Tuesday. The unattended Swiss Army-brand backpack, with wires visible, was discovered Monday morning on a downtown bench by three city workers who notified police of the device about 30 minutes before the parade was scheduled to begin, the FBI said. The parade, attended by about 1,500 people, was quickly rerouted while city's bomb disposal unit was summoned and safely "neutralized the device," the FBI said. FBI agent Frank Harrill, an agency spokesman in Spokane, described the "improvised explosive device" as having a "very lethal design" capable of inflicting "multiple casualties." The device in the backpack was largely concealed by two T-shirts packed inside. The exact design and suspected strength of the bomb were not revealed. But Harrill said the proximity of the bomb in time and space to an annual parade held on the national holiday marking the birthday of slain civil rights leader the Rev. Martin Luther King Jr., was "inescapable." Asked whether investigators regard planting of the bomb as a potential case of domestic terrorism, he said: "It falls squarely within that arena and is being investigated as such, and clearly the timing and location of the device would trend in that direction." The FBI posted a bulletin seeking the public's help in the investigation and offering a $20,000 reward for information leading to the arrest and conviction of any individuals responsible for the bomb. Investigators also asked anyone who took photographs or video footage in the area where the pack was found during a three-hour period before the parade to contact the FBI.