Police say 29-year-old Paul Harris practiced voodoo and kept the head of 49-year-old James Gerety to talk to after the March or April 2011 killing.
The Topeka Capital-Journal reports that Gerety's partial remains were found a year later in Carbondale, 18 miles south of Topeka.
Harris' former girlfriend testified in March that he told her he used a guitar string to sever Gerety's head. She said he disposed of the body but kept the head in a bag.
A Topeka police officer said the ex-girlfriend told him Harris practiced voodoo and that he liked to talk to the head.