Terry Dewayne Smith Sr. told reporters on Thursday that his son – who authorities believe is now dead – isn't autistic as police and his ex-wife have claimed.
The man's son went missing about three days ago, and police have arrested a half-brother in the case after discovering human remains near the family home.
The Associated Press reported that Smith Sr. disputed claims his son, Terry Dewayne Smtih Jr., was autistic.
"He was a very bright, well-adjusted child, at least he was when he left here," Smith Sr. told the AP.
The young boy left his father's home in West Virginia two years ago to live with his mother in California.
The 16-year-old stepbrother has been arrested, after authorities uncovered what appear to be the buried remains of a child on the family property.
Smith Jr., who is reportedly a "high-functioning" sufferer of autism, has been missing from the Californian town of Menifee since Saturday.
Hundreds of volunteers were extensively searching for the boy until the remains were discovered Wednesday.
The remains fit the Smith's description and were buried in a shallow grave, evidence enough to take the child's 16-year-old stepbrother into custody for further questioning.
More from GlobalPost: Amber Alert seeks money to support missing child searches
One of the last people known to have seen Smith alive, the name of the older boy has not been released to the public.
"The brother was walking away from their residence, turns back, sees that Terry's following him and tells Terry, 'Hey, go home,'" said Riverside County police deputy Albert Martinez to the Desert Sun Newspaper.
"One of the things I want to stress is that this is a domestic issue within that residence, and that there is no stranger in the city of Menifee that caused this to happen," said Menifee city Police Chief John Hill in a press conference Wednesday, Reuters wrote.
"We conducted multiple searches of the property and were diligent about doing so. Search dogs were used at the property, volunteers and personnel on multiple occasions," Hill added, according to NBC Los Angeles. "Sometimes it takes a while for us to put all the puzzle pieces together in a circumstance like this."
A Facebook page set up for the volunteer effort to find Smith read late Wednesday: "PLEASE REMEMBER that our focus has always been on Terry Smith, an 11-year-old boy. Our focus is still on that boy and the memory. Negative comments here about the family, the search efforts or organization or anything else are not going to help Terry's memory."