Ashlee Buzzard, the mom of missing 9-year-old Melodee Buzzard, allegedly switched license plates during their road trip in an apparent effort to avoid detection, according to authorities.

On Oct. 7, Melodee and her mom left on a three-day road trip from Lompoc, California, to the Nebraska area, the Santa Barbara County Sheriff’s office said. Surveillance images show the 9-year-old — in what appears to be a wig — at a Santa Barbara-area rental car business on Oct. 7, authorities said.

The last verified sighting of Melodee is now determined to be Oct. 9, sheriff’s spokesperson Raquel Zick told ABC News on Monday. Surveillance video shows Melodee with her mom that day near the Colorado-Utah border, Zick said.

The next day, on Oct. 10, Ashlee Buzzard came home to Lompoc with the car she and Melodee had rented on Oct. 7 — but Melodee was not with her, the sheriff’s office said.

Zick said investigators are now focused on the timeline from Oct. 9 to Oct. 10.

During the road trip, Ashlee Buzzard allegedly removed the car’s California license plate, Zick said, and she allegedly switched back to the original plate when she returned home.

It appears “the license plate was switched to avoid detection … don’t have any other plausible reason,” Zick said.

Melodee is still considered a missing person, and no arrests have been made, Zick said.

Ashlee Buzzard has not cooperated with the investigation, according to authorities. Investigators returned to the Buzzard home last week for a follow-up search.