Who Killed Mickey Spillane?

Oh right, pulp fiction author Mickey Spillane is dead, they won't release the details of why or how and we're supposed to believe he died peacefully? I ask you again, who killed Mickey Spillane? Until the mystery is solved, enjoy this description of a scene from his breakout book "I, The Jury" --

Hammer became so angry at a female psychiatrist that he shot her in her “stark naked” stomach. (“Stark naked” was a phrase that Mr. Spillane rather liked.) As she died, she asked, “Mike, how could you?” To which Hammer replied, “It was easy.”