The 10-year-old Riverside boy accused in the shooting death of his neo-Nazi activist father gave police a chilling account of how he carried out the early morning attack May 1, officials said in a court document.

The boy -- who told authorities he was tired of his father, Jeffrey R. Hall, beating him and his stepmother -- grabbed the family's Rossi .357 revolver from a closet and then "he went downstairs with the gun, pulled the hammer back, aimed the gun at his dad’s ear while he was asleep and shot him," Riverside Police Det. Greg Rowe wrote in a court declaration filed Tuesday. The boy "then went upstairs and hid the gun under his bed," Rowe wrote.

The declaration was filed to support allegations against the boy's stepmother, Krista F. McCary, 26, who was charged Tuesday with child endangerment and failure to properly store a firearm.

McCary told detectives that her stepson "knew how to shoot guns" and that her husband took the 10-year-old target shooting while the two were patrolling the Mexican border with the National Socialist Movement, a neo-Nazi group, according to the declaration. Hall was the leader of the group in the western United States.

Document: Read the court papers

Along with recovering the handgun used in the shooting, police reported that they found an unloaded .22-caliber rifle in the Hall home's garage, 10 feet away from an unlocked ammunition cabinet. They also said they found several "edged weapons" in the master bedroom, according to the court document.

The boy's 9-year-old sister told police that she knew where her parents kept all of their guns and that she had been target shooting with her mom and dad, but was told not to touch the gun, the court document stated.

A juvenile court judge on Wednesday ordered the boy to undergo a mental health evaluation.

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Read the court documents in neo-Nazi slaying

-- Phil Willon in Riverside

Photo: Jeffrey R. Hall in 2010. Credit: Sandy Huffaker / Associated Press