COLUMBIA, Mo. -

New charges filed Thursday against a man who admitted to killing 6-year-old Dane Hathman claim he stole the suspected murder weapon from his father.

The new filing comes from Boone County court, charging 27-year-old Scottie Willet for stealing a firearm. Callaway County Sheriff Dennis Crane says he suspects Willet of murdering Hathman with a Hi-Point .40-caliber handgun while babysitting him at the Hathman's house on Primrose Lane.

The Boone County Sheriff's Department said in a probable cause statement Willet's father reported his gun, a Hi-Point .40-caliber handgun, stolen Thursday morning around 3:30. Willet's father, who lives in Harrisburg, told investigators he had not seen his gun since August 21, and he never gave his son permission to borrow the gun. A friend told Willet's father was seen with a firearm, which "prompted him to check on his firearm and found it missing."

Sheriff Crane said his department received a missing person call related to Hathman around 2:30 Thursday morning - an hour before the report of a missing gun. He said deputies found Hathman in Willet's bedroom, shot "multiple times."

Pettis County sheriff's deputies arrested Willet in Sedalia around 6:50 a.m. Thursday when they located the car Willet stole from Dane Hathman's mother. Deputies found a handgun in the car. The Boone County probable cause statement said Captain Dave Keller of the Pettis County Sheriff's Department confirmed the serial number on the gun found in the car as the same one stolen from Willet's father's house. 

Sheriff Crane said Thursday Willet lived with the Hathman family since as early as January. Callaway County prosecutor Chris Wilson charged Willet with first-degree murder.