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Authorities believe they found the body of 3-year-old Mariah Woods in a creek outside Jacksonville, North Carolina, the FBI said Saturday. She had been missing for nearly a week.

FBI spokeswoman Shelley Lynch said a dive team discovered the girl's remains alongside Shaw Highway in rural Pender County near Shelter Creek, a tributary of the Northeast Cape Fear River.

Mariah Woods Courtesy of Onslow County Sheriff's Office

Woods' family had been notified of the discovery, Lynch said.

Earlier Saturday, authorities announced an arrest in the case and said that the 3-year-old girl who had been missing since Monday was presumed dead.

Related: Search for missing North Carolina 3-year-old enters third day

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Earl Kimrey, the 32-year-old live-in boyfriend of Mariah's mother, was taken into custody late Friday and charged with concealing a death and second-degree burglary, among other charges, the Onslow County Sheriff's Office said. He was being held on a $1 million bond.

The FBI said Kimrey was likely to make an appearance in court on Monday.

"Due to the evidence gathered during the course of the investigation, it is believed that Mariah is deceased," Onslow County authorities and the FBI said in a joint statement.

Earl Kimrey Onslow County Sheriff's Office

Authorities said they have not yet located Mariah's body, and the missing persons search that included FBI agents and K-9 units will now shift to a recovery effort. They added that additional charges could be filed against Kimrey.

Mariah was last seen Sunday night, when her mother, Kristy Woods, said she put her to bed in their home in Jacksonville, near the Camp Lejeune military base. Woods said her boyfriend, Kimrey, also checked on her around midnight. She told police that she went to her room again Monday morning after 6 a.m., and she was gone.

That's when she called the police.

Family members told NBC affiliate WRAL that Kimrey lived in the home with Mariah and her mother. State records show that Kimrey had previously been charged with a series of small crimes dating back to 2005, the station said.

On Friday, Onslow County Sheriff Hans Miller said he was "overwhelmed" by the outpouring of support from the community and nearby military members, who came out to assist in the search for Mariah.

"We had a total of 730 volunteers help us today," Miller said. "All with one mission: to help us find Mariah."

FBI Special Agent-in-Charge Stanley Meador said authorities spent days searching by foot, boat and in the water for any leads. Meador said they also sifted through roughly 95,000 pounds of trash by hand for evidence, and some "items of interest" were sent to the Marine Corps Base at Quantico, Virginia, for testing.

"It does not appear that they are related to this case, but they will be collected and turned over to investigative teams for further review so that we are 100 percent certain," he added.