(CNN)The search for 5-year-old Taylor Rose Williams has expanded beyond Florida into Alabama.
Taylor has been missing since Wednesday, when an Amber Alert was issued. Law enforcement officials are now asking anyone who saw Taylor or her mom between Jacksonville and Alabama to come forward, said Jacksonville Sheriff Mike Williams during a press conference Monday. Taylor's mother is not missing, but she is also not cooperating with authorities, Sheriff Williams said.
Specifically, efforts are focused on the area around Demopolis and Linden in western Alabama near the Mississippi border, Williams said. The sheriff urged anyone who may have seen Taylor with her mother in the last six months to call investigators.
The sheriff said Taylor's mother, Brianna Williams, would have been traveling in a black 2017 Honda Accord with tinted windows and black rims.
Brianna Williams has stopped cooperating with police, the sheriff said.
"She has not spoken to us since Wednesday and she was the last person to see Taylor," Sheriff Williams said. "She is a person of interest in this case and we still need her cooperation in our efforts."
In contrast, Taylor's extended family has been talking to authorities and "very cooperative," the sheriff said.
CNN has reached out to Taylor's mother and other family members but has not heard back.
FBI offices in Jacksonville and Mobile, Alabama, as well as other law enforcement agencies, are assisting with the search, FBI Special Agent Rachel Rojas said.
Brianna Williams is not in custody. She continues to reside and work on the naval station in Jacksonville, Sheriff Williams said.