Mark David Chapman
It is believed that Chapman will never leave prison in his lifetime, because of the impact of his crime and the many death threats he has received over the years from other inmates and Beatles' fans. His name has been used in arguments promoting gun control, claiming that he would not have killed Lennon if he could not get a gun. (It is counterargued, however, that his plan was not simply to shoot Lennon, but to kill him; if he could not have used a gun, he would likely have tried another way. Abrams's later attack on Harrison supports this argument.)