Hargon, who was indicted by a grand jury on capital murder charges last week, said he didn't kill his cousin's family at their rural Yazoo County home on Valentine's Day.
Michael and Rebecca Hargon and their four-year-old son, James Patrick, vanished from their home in the Vaughn Community.
At the scene, authorities found blood and bullet casings but no bodies. The case made national headlines. Sixteen days later their bodies were discovered in a wooded area not far from Earnest Lee Hargon's home in Smith County.
Jennifer Hargon, Michael Hargon's sister, said she hoped Earnest Lee Hargon would admit to the killings.
Lewis set a Dec. 6 trial date and told attorneys to have motions and pleadings ready by Nov. 22.
The proceedings were held under tight security and lasted only a few minutes.