George C. "Tiny" Mercer (August 31, 1944 – January 6, 1989) was an American man who was convicted for the rape and murder of 22-year-old Karen Keeton in Belton, Missouri, on August 31, 1978. At the time of the murder, Mercer had a charge pending against him of raping a 17-year-old girl. He was executed at the age of 44 by the state of Missouri by lethal injection. He became the first person to be executed in Missouri since 1965. His execution was carried out in the former gas chamber which was converted to use lethal injection. Murder of Karen Keeton Late on August 30, 1978, George Mercer went drinking with friends from one of his motorcycle gangs at a lounge in Grandview, Missouri. While there, he noticed 22-year-old Karen Ann Keeton, who was working at the lounge as a waitress, and commented to a friend that he would like to sleep with her. Prior to the day of the murder, Mercer and Keeton had never met. One of Mercer's friends, Steven Gardner, approached Keeton and invited her out to breakfast with him, after which the two would visit Mercer's house in Belton, Missouri. His plan was to hand Keeton over to Mercer as a "birthday present," since the next day was Mercer's 34th birthday. Mercer then left the lounge with David Gee, a fellow gang member, and went back to his Belton home, arriving shortly after midnight on August 31. Another of Mercer's friends, John Allen Campbell, was already at the house babysitting Mercer's 10-year-old daughter, who was at the house and witnessed parts of the ensuing assault and murder. Shortly after Mercer and Gee's arrival, Gardner and Keeton arrived at the house as well. Mercer then threatened Keeton with a sawed-off double-barreled shotgun and ordered her to go upstairs to his bedroom. When she hesitated and asked Gardner for help, Gardner responded, "Happy birthday, Tiny," directed towards Mercer. Mercer raped Keeton in his bedroom; later, Gardner sexually assaulted her as well, followed by David Gee. Gardner also stole money from Keeton's purse. After the multiple sexual assaults were over, Campbell would later testify that he went upstairs to comfort the victim, who was crying; afterwards, he fell asleep. Mercer headed upstairs afterwards, and on his way, he passed Gardner; he asked Gardner what they should do with the victim, and Gardner replied that they should kill Keeton. Mercer