Shannon L. O’Roark Griffin, a former NASA contractor, allegedly killed her Air Force Colonel husband’s psychiatrist mistress after learning of the affair.

In a marriage counseling session in Great Bend, Kansas, Roscoe Griffin told his wife that he had a mistress and that he was unwilling to end the affair, according to the Kansas City Star.

Shannon, 52, then left the session, hopped in the car, and drove the 250 miles drive to Irina Puscariu’s house in Kansas City, Missouri, where Shannon allegedly shot Puscariu, 46, three times in the head, ABC News reported. “She did what had to be done to protect him and others from this evil woman,” court documents said.

Shannon called her daughter and husband on her drive back to Kansa, confessed to the murder, and was subsequently pulled over by police, who tracked her location using her cell phone.

She lived in Houston for decades where she worked as a training specialist at Johnson Space Center, the Houston Chronicle reported. Her husband also worked for NASA, as a computer instructor, in the 1980s.

This story has a much unhappier end than that of Lisa Nowak, the astronaut who infamously donned a diaper as she drove to Florida to confront her astronaut husband’s mistress, an Air Force captain.