Edward James Whalen

Few things are known about Whalen, apart from the fact that he spent most of his life behind bars for numerous larcenies and that he was twice deemed unfit to stand trial. He has revealed that he was given a contract to kill Jim Garrison by David Ferrie, a contract that he says was financed by Clay Shaw and Dean Andrews.

Source:
http://mcadams.posc.mu.edu/russ/testimony/whalen.htm