A bomb planted along the route of a Martin Luther King Day parade in Spokane, Washington, appeared to have been an attempt at a sophisticated attack, according to statements made by law enforcement officials.

Spokane police said this week that the bomb -- which was found before the parade began on January 17 and defused -- may have contained a chemical commonly found in rat poison, potentially in an effort to inflict even greater damage on its victims.

According to the Spokesman-Review, "rat poison has been added to bombs in the Middle East for the stated purpose of acting as an anti-coagulant – which inhibits the ability of bleeding wounds to clot."

There has been controversy over whether reports of rat poison in insurgent bombs are accurate. Nonetheless, it may be possible that the perpetrator was someone who was familiar with the tactics of Middle Eastern insurgencies.

"It’s not like some of the other types of devices I have seen in Spokane or in my career," Spokane Police Chief Anne Kirkpatrick told the press. "This is one of sophistication.”

Officials also told the newspaper that the backpack in which the bomb was planted was placed such that its blast would target marchers in the parade.

FBI officials said earlier their believed the bomb to be an act of "domestic terrorism" and suggested the failed attack may have been racially motivated.

The Statesman Examiner notes that eastern Washington state, where Spokane is located, "has been the location of multiple incidents of anti-government and white supremacist activity for over two decades."

Federal investigators are also investigating an explosive device that was found last March near the U.S. Courthouse in Spokane. An arrest has not been made in that case.

Another bomb packed with shrapnel exploded outside Spokane City Hall in the spring of 1996. Federal prosecutors indicted white supremacists Chevie Kehoe of Stevens County and Danny Lee of Oklahoma for that bombing. Both were ultimately convicted of a 1996 triple homicide in Arkansas.

FBI Special Agent Frank Harrill said investigators aren't ready to name any suspects in the case. The bureau has offered a $20,000 reward for information leading to a suspect.