Suffer-Not-Injustice is pure Oliver Cromwell. Vimes, however, is closer to your detective character in Film Noir, specifically Dirty Harry. I think the L-Space annotations point out how many detective-movie cliches appear in Guards! Guards! (The flickering glowing-lettered sign, the rain, shooting the lock off a door, and the "Do you feel lucky" speech as adapted for use with a dragon...). Also, I agree with Vimes. "Family history of regicide" makes it sound like it was a habit. Lorenzo *was* only one king...