Authorities say Neff was shot once in the back of the head outside of his bar in Poteau. His body was discovered three days later in a strip pit near Pocola.
The Oklahoma State Bureau of Investigation said Neff was found with his hands and legs bound with wire and zip ties, duct tape wrapped around his head and with a cement block chained to his body.
District Court Judge Jon Sullivan handed down the life sentence Thursday to Nichols.
The Associated Press contributed to this report.
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