On Oct. 15, 2004, Mary Elizabeth Schipke entered the Oracle post office to buy a 47-cent stamped envelope. When she got frustrated with the clerk behind the counter, she told her: "God, I pray a bomb falls on your stupid, fucking head."

Almost a year later, Schipke was convicted of threatening a federal facility with weapons of mass destruction. Schipke describes what she told the clerk that day as an "imprecatory prayer"—basically, a simple curse—but that defense didn't keep her from serving a four-year prison sentence, with the last two years at Carswell, a women's federal medical prison outside of Fort Worth, Texas, that has been the subject of allegations about the questionable care of prisoners with physical and psychiatric conditions.

Although now free and on supervised release, Schipke, 51, continues to fight the federal government—this time, over a DNA sample forcibly removed from her in prison. After her release, priso