The Federal Bureau of Investigation is investigating an anti-government group's threats against governors in 30 states.
The Guardians of the Free Republic sent letters last week telling both Republican and Democratic governors to step down or be removed.
The FBI fears the group could encourage others to act violently and it is warning law enforcement officials across the country to be alert.
Tim Cox, a non-partisan grassroots political leader in Texas, says the group tried several times to recruit him.
"The truth is, everywhere there are crazies," said Cox, founder GOOOH, a movement seeking to replace all members of the House of Representatives with what he calls true citizen representatives. "But you can't have violence. You've got to put an end to that immediately."
While intelligence officials have cited no specific evidence of plans by the group to use violence, they've admonished police authorities to take the letters "as a justification for violence or other criminal actions."
Last week's incident is the latest in a trend of anti-government sentiment following the recent passage of the largely unpopular health care bill.