JACKSONVILLE, Fla. – The mother of a 5-year-old girl reported missing from Jacksonville last week is now a person of interest in her daughter's disappearance, Jacksonville Sheriff Mike Williams announced Monday, a day before remains were found in a wooded area in Alabama where investigators had been searching for Taylor Rose Williams.

They have not yet identified the remains, and Brianna Williams, the girl's mother, is not facing charges.

But Sheriff Williams asked anyone who saw Taylor and her mother, Brianna Williams, together between Jacksonville and Alabama in the last two weeks to call the Sheriff's Office with that information. The number is 904-630-0500.

He said Brianna Williams was believed to have been driving her black 2017 Honda Accord, which has tinted windows and black rims.

Sources previously told News4Jax that cadaver dogs had gotten a scent on the car, and it was taken into evidence.

Sheriff Williams said Monday that Brianna Williams is considered a person of interest in her daughter's disappearance.

He said she hasn't spoken to police since last Wednesday -- the day she reported her daughter missing -- and is not cooperating with the investigation.

"We still need her cooperation," Sheriff Williams said.

Dozens of members of the Jacksonville Fire and Rescue Department's Urban Search and Rescue team traveled to Demopolis, Alabama, on Monday to continue searching for Taylor.

The sheriff said the USAR team, which left town in the early afternoon from the department's training academy, would coordinate with local authorities as the search continued.

Around 1 p.m. Tuesday, authorities in Alabama announced that remains had been found in a wooded area between Linden and Demopolis, but they have not officially identified them yet.

Demopolis, a small town of about 7,000 people, is about a 7.5 hour drive from Jacksonville, west of Montgomery.

"We feel pretty comfortable that this is the right step to take to bring some closure to this case. ... The information that drove us to Alabama demanded this kind of response," Sheriff Williams said.

UNCUT: Sheriff Williams' Monday news conference

The firefighters with USAR are specially trained for searching for missing people in criminal cases and after natural disasters. The department K-9 unit was also dispatched.

"There's already a lot of work going on even before the boots actually hit the ground," said Randy Wyse, president of the Jacksonville Association of Firefighters. "It's a continual process of performing a search, coming back and determining what you found, and then planning for the next work cycle -- where you're going to search again. It's a day-to-day growth of how far and how wide the search pattern is."

Firefighters said they expected to be on the assignment for up to seven days.

Wyse said it's rare for the USAR team to be deployed out of state. The last time he remembers one leaving Florida was for Hurricane Katrina.

Homicide investigators were already working with the FBI in Jacksonville and Alabama, following leads, but the sheriff declined to give any more specifics. The FBI said they were helping to trace phone records, following Brianna Williams' recent movements.

Sheriff Williams said other family members investigators have spoken with are cooperating.

The investigation into Taylor's disappearance began at 7:22 a.m. Nov. 6 at a home on Ivy Street where Brianna Williams told police she last saw her daughter in bed the night before. Hundreds of officers, along with K-9 teams and mounted units searched extensively for two days.

Community members spent hours handing out flyers, knocking on doors, and combing through the neighborhood for any sign of the little girl.

At the same time, dive teams and investigators searched a Southside apartment complex where Brianna Williams recently lived.

The sheriff said the mother stopped cooperating with police the second day of the search after detectives pointed out inconsistencies in her story. Sheriff Williams also asked for anyone who had seen Brianna Williams together with her daughter in the last six months to contact call police at 904-630-0500.

Family members in Alabama told News4Jax that Taylor's biological father hadn't seen his daughter in about two years.

In the first few days after an Amber Alert was issued for Taylor, the Jacksonville Sheriff's Office said it received hundreds of tips from the community, but none so far leading to her whereabouts.

SHARE: Click for printable FDLE missing child flyer

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What qualifies for an Amber Alert?

GALLERIES: Police swarm neighborhood | Hundreds join search | Taylor Rose Williams

An Amber Alert remains in effect and the reward for information in her case is $4,000. To remain anonymous and be eligible for the reward, contact CrimeStoppers at 1-866-845-TIPS.