When Colorado's prisons chief was shot in the face last month and a Texas prosecutor was gunned down with his wife in their house last weekend—the second such assassination of a Lone Star DA since January—you could have looked at any number of suspects:

A district attorney in north Texas was shot along with his wife Saturday, their deaths coming only a few weeks after a prosecutor in the same district attorney's office was shot and killed outside the county courthouse.

In May, Texas police responding to a traffic accident came upon a dying 59-year-old man behind the wheel of a pickup truck. Heavily tattooed, and carrying several contradictory identification cards, the driver had apparently swerved into a concrete barrier for some unknown reason; he died later that night, just as…