In the latest unhinged threat on Barack Obama's life, a California man has been indicted by a federal grand jury after allegedly writing a deranged and racist email screed that urged recipients to "kill the 'president,'" and seemed to invoke the recent death of a Census Bureau worker in an apparent act of anti-government violence.

On September 28th, according to the indictment filed by prosecutors and examined by TPMmuckraker, John Gimbel of Crescent City sent an email whose subject line read:

Operation kill big-[epithet]-rig: kill the 'president' [epithet], then write 'fed shit' on his chest with a felt tip.

That last clause appears to be a reference to the recent death of a Census Bureau worker, who was found in rural Kentucky with a rope around his neck and the word "Fed" scrawled on his chest, in what many have suggested was an act of anti-government violence.

In the body of the e-mail, as reproduced in the indictment, Gimbel, 59, used a string of crude and racist epithets in additionally calling for the murders of Michelle Obama and the couple's two children "in front of" the president. You can read the sick diatribe here.

Prosecutors did not say who the email was sent to. Asked by TPMmuckraker, a spokesman for the US attorney's office declined to elaborate beyond the indictment.

Gimbel has a history of making threats against public officials, reports the San Francisco Chronicle. In 2004, he was accused of writing an email that complained about getting a $5 parking ticket then asked "all of the citizens of Crescent City to fix up some of these f- up piggos. Grab those hi-powered deer rifles, each and every, and get in groups of 50 and more and go breeze away to dust the skull of the police chief." The paper reports that Gimbel was convicted of making the threats, but that the conviction was overturned on appeal.

In a separate case, Gimbel was accused of leaving vulgar messages on the voicemail of a sheriff's deputy who had cited him for having faulty brake lights and no proof of insurance. The deputy eventually obtained a restraining order against Gimbel.