Michael Lee Shaver Jr., 33, was charged Sunday with first-degree murder and armed criminal action related to a killing in fall 2001.
Shaver, who police say spontaneously confessed after he was arrested following a failed carjacking, told investigators that he had shot and killed seven people at his residence during drug transactions so he could take their money and drugs, Cass County Sheriff's Capt. Chuck Stocking said.
Shaver claimed that after he killed the men—all between the ages of 20 and 40 and from the Kansas City area—he dismembered the bodies, burned the parts in a fireplace in his bedroom, then used a hammer to crush large bones and skulls, Stocking said.
Shaver said he then spread the bone fragments around his back yard.
Investigators found bone fragments from two people Saturday on the plot of land northeast of Drexel in western Missouri, and were scouring the property for additional victims.
Authorities are not ruling out the possibility that he is exaggerating about the killings.
"He can say that he killed 50, but we have to prove that he actually did," Stocking said.
Shaver was arrested Friday after he lost control of his vehicle and wrecked, Stocking said. Shaver and his passenger, Nathan Wasmer, 27, tried to carjack a witness, but fled after they could not get into the woman's vehicle, Stocking said.
The witness told an emergency dispatcher that the two men were armed with guns. The men were tracked down to a residential area, where Wasmer surrendered after an hour-long standoff and Shaver was found about a half-hour later hiding in a nearby yard, officials said.
Stocking said Shaver told deputies as he was being placed into a patrol car that he had knowledge of human remains on the property where he lives, and that he wanted to talk to someone about it.
"It was a spontaneous statement he made while he was being interviewed for the carjacking," said Stocking.
"I didn't believe him," Stocking said. "I just flat didn't believe him."