The four people involved in the alleged plot -- the boy's mother, grandmother, aunt and a co-worker of the aunt -- have been charged with kidnapping and other felonies, the Lincoln County Sheriff's Office said.
"Family members told investigators their primary intent was to educate the victim and felt they did nothing wrong," the press release said.
During his reported ordeal the boy was lured Monday into a pickup after getting off his school bus, tied up, threatened with a gun, taken to a basement where his pants were removed, and told he could be sold into sex slavery, police said.
The boy was told in the truck by Nathan Wynn Firoved, the aunt's co-worker, that he would never "see his mommy again," and he would be "nailed to the wall of a shed," the sheriff's statement said.
The boy started to cry, police said, and Firoved, 23, showed the child a gun and said he would be harmed if he didn't stop bawling. Firoved used plastic bags to tie the child's hands and feet, police said. He took his jacket and covered the boy's head so he couldn't see.
He guided the boy, still unable to see, into the basement of the mother's home, where his 38-year-old aunt took off the boy's pants, according to the sheriff's statement.
"The victim remained in the basement for some time before he was unbound and told to go upstairs, where the victim's family lectured him about stranger danger," the statement said.
The suspects kept each other updated throughout the incident on cell phones, police said.
The boy's 25-year-old mother, Elizabeth Hupp of Troy, is charged with felony kidnapping and felony abuse and neglect of a child. The 58-year-old grandmother, Rose Brewer; the aunt, Denise Kroutil; and Firoved are also charged with felonious restraint.
The sheriff said Kroutil approached Firoved to kidnap her nephew to "scare" him because he was "too nice" to people. The statement alleges the mother and grandmother both agreed the boy should be kidnapped to teach him a lesson.
The boy was placed into protective custody after he told school officials Wednesday what had happened to him.
CNN has been trying to track down lawyers for the accused, but has been unable to locate information on the attorneys.
Troy is about an hour northwest of St. Louis.