Was Cummins fired as political retribution?

Yesterday in an interview, ousted U.S. attorney Bud Cummins raised the possibility that the Justice Department may have fired him because he decided to investigate “alleged corruption by Republican officials in Missouri amid a Senate race there that was promising to be a nail-biter.” In Jan. 2006, Cummins began looking into allegations that Gov. Matt Blunt (R) had “rewarded GOP supporters with lucrative contracts.” By June, the Justice Dept. had fired him. “Now I keep asking myself: ‘What about the Blunt deal?’” said Cummins.

UPDATE: In a message to TPMmuckraker, Cummins clarified, “I do not know of any connection whatsoever to the Missouri investigation and my firing. I am not asking myself (or anyone else) about that.”