Daniel Siebert was an American serial killer who passed away of pancreatic cancer on April 22, 2008 while awaiting execution. 
Siebert is known to have victims in California, Nevada and Alabama.

9" x 12" unsigned drawing was among Siebert's property when he died. It appears that Siebert didn't have time to finished this piece before his death. 
 
There are four different explicit scenes, laid out in comic book form. Four spots on the actual image have been obscured and remain visible on the actual artwork.