A MAN weighing 28 stone crushed his 11-year-old "autistic" step grandson to death after sitting on him to keep him under control, police said.
Donald Martin Jr, 58, was arrested and faces charges of reckless homicide over the death of schoolboy Dylan Davis.
Police in Brown County, Ohio, said Martin Jr was arrested on Friday after the boy's grandmother reported the boy wasn't breathing during a 911 call to police.
She told a 911 dispatcher: "He came home and he threw a fit. Police came here all the time for him and he threw a fit.
"My husband was holding him down, he got sick and then he just passed out. I don't know."
The grandmother, who is not being named, got into an argument with the six-stone boy, before her husband stepped in.
It appears the 11-year-old was deceased as a result of positional asphyxiation or compression, Sheriff Gordon Ellis told WLWT.
The victim's father, Sam Davis, told WLWT that his son was showing more anger issues as he got older.
Davis said his son got along with his step-grandfather and no one expected this. Mr Davis told the news station: "Everything was good across the board, this has come as a complete surprise. It's mind-blowing.
Prosecutors are claiming Martin kept the boy pinned down for several minutes and eventually ended his life. The investigation is on-going.