While politics isn't a factor in all of these recent violent killings, it certainly was a factor in the shooting deaths of the three Pittsburgh police officers. Here's an excerpt from a Pittsburgh Post Gazette article:

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Suspect in officers' shooting was into conspiracy theories
Sunday, April 05, 2009

By Dennis B. Roddy, Pittsburgh Post-Gazette

Richard Andrew Poplawski was a young man convinced the nation was secretly controlled by a cabal that would eradicate freedom of speech, take away his guns and use the military to enslave the citizenry.

His online profile suggests someone at once lonely and seething. He wrote of burning the backs of both of his hands, the first time with a cigarette, the second time for symmetry. He subscribed to conspiracy theories and, by January 2007, was posting photographs of his tattoos on white supremacist Web site Stormfront....

"He was really into politics and really into the First and Second amendment. One thing he feared was he feared the gun ban because he thought that was going to take away peoples' right to defend themselves. He never spoke of going out to murder or to kill," said Edward Perkovic, who described himself as Mr. Poplawski's lifelong best friend.

Mr. Poplawski's view of guns and personal freedom took a turn toward the fringes of American politics. With Mr. Perkovic, he appeared to share a belief that the government was controlled from unseen forces, that troops were being shipped home from the Mideast to police the citizenry here, and that Jews secretly ran the country.

"We recently discovered that 30 states had declared sovereignty," said Mr. Perkovic, who lives in Lawrenceville. "One of his concerns was why were these major events in America not being reported to the public."

Believing most media were covering up important events, Mr. Poplawski turned to a far-right conspiracy Web site run by Alex Jones, a self-described documentarian with roots going back to the extremist militia movement of the early 1990s.

Around the same time, he joined Florida-based Stormfront, which has long been a clearinghouse Web site for far-right groups. He posted photographs of his tattoo, an eagle spread across his chest.

"I was considering gettin' life runes on the outside of my calfs," he wrote. Life runes are a common symbol among white supremacists, notably followers of The National Alliance, a neo-Nazi group linked to an array of violent organizations.

"For some time now there has been a pretty good connection between being sucked into this conspiracy world and propagating violence," said Heidi Beirich, director of research at the Southern Poverty Law Center and an expert on political extremists. She called Mr. Poplawski's act, "a classic example of what happens when you start buying all this conspiracy stuff."