Authorities have not said whether they believe Michael and Rebecca Hargon and their 4-year-old son, James Patrick, are still alive. Blood and spent bullet casings were discovered at the family's home in Yazoo County.
"Any and all possibilities are still open at this point. Nothing has been ruled out in terms of the Hargon family and their condition," said State Highway Patrol spokesman Warren Strain.
Earnest Hargon, an adopted cousin of Michael Hargon, was charged in Smith County with a single count of possession of methamphetamines while also in possession of a firearm.
Earnest Hargon also faced an arraignment on Monday in Yazoo County, north of Jackson. Authorities said he would face multiple felony charges, but they did not say what the charges would be.
Authorities for two days searched near Earnest Hargon's 160-acre Smith County property, using helicopters, dogs, horses, and manpower, reports CBS News Correspondent Cynthia Bowers. Police said possible evidence was found at the property but would not elaborate.
"We've done everything we can do here," Strain said Sunday. "Not being able to locate the Hargon family will have zero effect on going forward with the charges."
Investigators also have been checking a piece of land that Michael Hargon recently inherited from his uncle, Charles Hargon, to determine if it is linked to the disappearance, said Jennifer Hargon, Michael's sister.
Earnest Hargon, Charles Hargon's adopted son, was not included in the will, she said. Strain said the Madison County property is a consideration in the case, but not necessarily a motive.
"It could be a potential motive, but it's not the only one," Strain said, adding that other evidence collected in the searches has linked Earnest Hargon to the family's disappearance. He declined to elaborate.
When arrested, Hargon was carrying less than an ounce of meth, authorities said Sunday. The firearm he allegedly had was is an AR-15 assault rifle, which Strain said could be converted into an automatic weapon.