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An unidentified 16-year-old family member has been arrested in the death of Menifee, Calif., boy Terry Smith, city Police Chief John Hill said Wednesday afternoon.
Earlier, on the fourth day of a search for the 11-year-old that brought out hundreds of volunteers, Hill said partially exposed human remains had been found in a shallow grave of the backyard of the Smith home.
The occupants of the Smith home had been interviewed by investigators at the police station after investigators responded early Wednesday morning to a report of remains found, Hill said.
"As a result of those interviews, a 16-year-old family member was arrested," Hill said.
Hill would not identify the family member who had been arrested or give any information about the suspect.
Earlier in the day, investigators had served a search warrant at the Smith home and authorities had been attempting to determine whether remains found behind the residence were those of the missing child, according to the Riverside County Sheriff's Department.
Law enforcement agents suspended their search for missing 11-year-old Terry Smith Wednesday morning as investigators blocked off the area with yellow crime scene tape.
Aerial video showed investigators with a rake, shovel and other hand tools in a large dirt field behind the property. The dig area was along a fence line next to a large tree behind the Smith residence.
Authorities placed what appeared to be a body on a gurney.
The boy's mother, her partner and a 16-year-old step-brother were being questioned at the sheriff's station, according to the Riverside County Sheriff's Department.
Hill refused to say whether the stepbrother was the suspect.
Terry, who has autism, was last seen Saturday at the family home in the 33000 block of Helen Lane in Menifee, about 80 miles southeast of downtown Los Angeles.
Deputies suspended the law enforcement search for Terry early Wednesday, but volunteers continued the search late into the morning.
Some searchers clasped hands in prayer as deputies were digging.
"We're still holding out hope," said volunteer searcher Bill Gillette. "That's all we have to go with, right now. There wasn't anything specific enough for us to stop looking."
Riverside County Sheriff's Department and forensics services vehicles were at the family's home.
"He's alive. I know he is," his mother, Shawna Smith, told NBC4 Tuesday. "Mommys' hearts don't lie. He's still here -- he's somewhere; we just need to find him."
On Tuesday, Menifee police said investigators had no leads after speaking to registered sex offenders in the area about the case.
At about 7:30 p.m. Saturday, the boy's mother went out to play pool with some friends and left Terry with his older step-brother. When their mother checked in on them at about 1 a.m., she thought they were asleep.
In the morning, Shawna Smith discovered Terry was missing when she went into the bedroom to give him his medication. She reported him missing at 10:30 Sunday morning.
Terry's step-brother said he last saw the boy walking on Helen Lane Saturday night near the family home.
"It's just sadness," said volunteer searcher Angeles Adams, a teacher. "We've lost one of our students."
A vigil is scheduled for 7:30 p.m. Wednesday at Menifee Market, where a civilian search team was stationed.
Anyone with information in the case can contact authorities in Menifee at (951) 210-1000 or the Riverside County Sheriff's Department dispatch line at (951) 776-1099.