Search for Missing Tennessee Girl Carlie Trent Continues

It's been six days since 9-year-old Carlie Trent went missing with her uncle in Rogersville, Tennessee. The blonde hair blue eyed girl was last seen when her uncle, Gary Simpson, picked her up from school on Wednesday, PEOPLE confirms.

Simpson allegedly told teachers that Carlie's dad had been in a car accident and he was sent to get her. Josh DeVine of the Tennessee Bureau of Investigation tells PEOPLE this was a lie and Simpson had no authority to pick up Carlie that afternoon.

Simpson, 57, previously had custody of Carlie and her younger sister up until recently when they were returned to their biological father, James, DeVine says.

While DeVine says authorities do not believe Simpson wants to harm his niece, an Amber Alert – the highest response for a missing child in the state of Tennessee – has been issued. The motive for the alleged kidnapping is still unknown, DeVine tells PEOPLE.

Authorities originally issued an endangered child alert because of Simpson's relationship to Carlie, however, the alert was raised to Amber after a warrant for kidnapping was issued on Thursday.

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According to surveillance footage, before Simpson allegedly kidnapped Carlie, he went to a local Walmart to buy camping gear.

Afterwards, Simpson allegedly brought Carlie to a local grocery store and bought non-perishable food items. In the video, Carlie doesn’t appear to be distressed.

"At the end of the day she did have a relationship with her uncle – she lived with him for sometime – so there's reason to believe that she trusted him to some extent," DeVine says.

Simpson's purchases have led authorities to believe that Simpson planned on camping outside with Carlie. DeVine says helicopters are now being used to search the countryside, however, the changing seasons and rural landscape makes searching more difficult: "It's kind of like a needle in a haystack."

With the one-week mark approaching, locals have been showing their support for the Trent family.

"This is a very small town, it's very tight knit and [the community] has put purple ribbons up everywhere. [Carlie's] school wore purple today in support of her," DeVine says. "There are plenty of people that are holding out on hope."

Carlie is described as 4'8" tall, weighing about 75 lbs. with blonde hair and blue eyes. She was last seen wearing a black and grey tank top with blue jeans. Simpson was last seen wearing a brown cap with a dark colored shirt and blue jeans.

Anyone with information regarding Carlie or Simpson's whereabouts is urged to contact the Tennessee Bureau of Investigation at 1-800-TBI-FIND or the Rogersville Police Department at (423) 272-7555.