The boy has been warned he will face trial as an adult and could face more than 40 years in prison, the woman told The Associated Press in a phone interview from her home in the Akron area.
"My son is not a monster," she said. She stopped short of saying he provided the tip that led to the discovery of a body near an Akron-area mall on Friday but said he "has told everything he knows."
The AP is not naming the mother to shield the identity of the juvenile crime suspect.
Authorities say a phony Craigslist ad for a farm hand in southeastern Ohio was used to lure men into the robbery scheme. Police believe two deaths are connected to the scam but haven't said whether another body found Friday is linked.
The farm advertised on Craigslist does not exist; the remote Noble County area where two bodies were found 90 miles south of Akron is property owned by a coal company and often leased to hunters.
Richard Beasley, 52, has been jailed on unrelated prostitution charges.
Beasley's mother has described his relationship to the teen as that of a mentor. She previously told the AP that her son has "a very caring heart" and that she prays reports he is a suspect are not true.
But the teen's mother said Monday that the boy felt threatened by Beasley, telling her that Beasley once said that he knew where the teen lived and that "I know where your mother lives."
The mother said she has been inundated with calls from those who know their son, saying he wasn't capable of violence. She urged prayers for victims' families and for her son's exoneration.
"Pray for the families and pray that America and everybody else finds the real monster that robbed these families of their men," she said.
A South Carolina man answered the ad and was shot in Noble County on Nov. 6 before escaping, police say. The body of Norfolk, Va., resident David Pauley, 51, was found the following week.
Timothy Kern, 47, of Massillon, was found buried Friday near the mall in Akron. He had been shot in the head.
A third body was found Friday not far from where Pauley's was buried in a hand-dug grave.