Three young children kidnapped from the Los Angeles area after their mother was killed have been returned to California from New Mexico as investigators shift their focus to filling in the gaps in the case.

The children, between 2 and 5, were flown back to the Los Angeles area Thursday night, Los Angeles County sheriff's Capt. Steve Katz said Friday.

They're in the custody of the Department of Children and Family Services, which will decide whether they can be placed with family.

Meanwhile the couple wanted for their kidnapping, Joshua Aaron Robertson, 27, and Brittany Humphrey, 22, were being held in Pueblo, Colorado, where they were arrested without incident Thursday night.

It was unclear whether they had attorneys.

Robertson and Humphrey are considered persons of interest in the death of Humphrey's half-sister, Kimberly Harvill, whose body was found with multiple gunshot wounds along a road in a remote area of Los Angeles County on Aug. 14.

Katz said detectives were expected to fly to Colorado on Saturday to interview the couple and get answers about what happened to Harvill.

"We really do need to find a few more pieces to the puzzle to get a better idea of events and how they transpired," he said.

Humphrey and Robertson, who authorities had said should be considered armed and dangerous, were found by Pueblo police officers conducting an unrelated fugitive roundup at a local motel where the couple was staying, the sheriff's department said.

A baby girl, who is Robertson's, was found unharmed and was in state custody.

Katz said he didn't know whether the couple had a gun with them, and Pueblo police declined to answer questions about the case.

A day before their arrest, Harvill's three children were found safe at a motel in the outskirts of Albuquerque, New Mexico.

Police said Robertson and Humphrey had asked a man at the motel to watch the kids and that he called police when the couple didn't return.

The children's father, Kenneth Chad Watkins, killed himself by lying in front of a train last September, according to the Fresno County Coroner.

Harvill and the children had most recently lived in Fresno and were transitory, moving from motel to motel, Katz said, adding that they depended on panhandling to survive.

In the days before her death, Harvill was staying with the children in Lebec, the unincorporated area of Los Angeles County where Robertson and Humphrey were living and where Harvill was killed.

Harvill, Humphrey and Robertson were all involved in methamphetamines, detectives said.

Investigators said they knew of no ongoing conflict between the sisters.

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