Updated

The search for four-year-old Athena Brownfield, who has been missing for nearly a week, is now being considered a "recovery operation," Oklahoma authorities said Monday. 

The Oklahoma State Bureau of Investigation said its agents, along with its partners at the Oklahoma Highway Patrol (OHP) have searched areas of Caddo County for the toddler’s remains. 

Ivon Adams, Athena Brownfield, and Alysia Adams

Ivon Adams and Alysia Adams have been arrested in connection with the disappearance of Oklahoma toddler Athena Brownfield. (MCSO, NCMEC and OSBI)

Brownfield was reported missing on Jan. 10, 2023, after a postal carrier found her five-year-old sister Alysia Adams outside the family home in Cyril, Oklahoma with no adult supervision. The postal carrier notified the Cyril Police Department which launched an investigation. 

Brownfield’s caretaker, 36-year-old Ivon Adams, was arrested in Arizona Thursday on one count of child neglect. On Friday, Adams’ charges were upgraded to first-degree murder

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Adams is being held in the Maricopa County jail in Phoenix pending extradition to Oklahoma, the OSBI said.

Earlier, Oklahoma authorities arrested Alysia Adams, 31, on two counts of child neglect, the bureau said in a statement late Thursday. Alysia Adams, who the OSBI said is married to Ivon Adams, remained jailed in Oklahoma's Caddo County on Friday.

The bureau released no further details about the arrests. It was unclear whether either Adams had an attorney to comment on their behalf.

A photo of Athena Brownfield

Athena Brownfield, 4, has been missing since at least Tuesday and authorities are continuing to search for her. (Oklahoma State Bureau of Investigation)

The girls had been in the care of Alysia and Ivon Adams, and Athena's sister was taken into protective custody, the bureau said.

Authorities said they believe Athena was wearing a hoodie with a butterfly design when she disappeared.

Volunteers and multiple law enforcement agencies have been involved in the search, which included a helicopter, boats, all-terrain vehicles, a specially trained ground team, and a review of surveillance video from around Cyril.

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The city of Cyril has also suspended trash service as investigators search for clues. The bureau said agents were following up on tips coming from Oklahoma and other states.

The Associated Press contributed to this report.