Questions are mounting as a massive search is underway for an Alabama woman who vanished from a highway after stopping to help a toddler. Carlethia “Carlee” Nichole Russell was last heard from on Thursday (July 13) night while on her way home from work. She was driving on I-495 South when she spotted a toddler walking along the interstate alone.

She first called 911 and then her sister-in-law before she stopped to check on the child around 9:30 p.m. “The family member lost contact with her, but the line remained open,” wrote the Hoover Police Department in a Facebook post on Friday (July 14). When officers who had been en route to Carlee’s location, near mile marker 11, arrived, she had disappeared, leaving behind her vehicle and personal belongings that were found nearby. The toddler was also nowhere to be found.

“A single witness has reported possibly seeing [a] gray vehicle with a light-complected male standing outside of Carlee’s vehicle, but we have no further information on that individual or the vehicle at this time,” said Lt. Daniel Lowe during a news conference on Friday, reports CBS News.

Talitha Russell, Carlee’s mother, also spoke to the media about her daughter. “She’s known to be helpful, and she has a big heart,” said Talitha. “And she does know not to stop for anyone, even a child on the side of the road. But she did call 911. And I think she kind of let her guard down, thinking they [the police] were so close. And when she got out [of] the car, she did tell my daughter-in-law, ‘I can’t just leave this little child on the side of the road.'”

At this time, a reward of up to $25,000 is being offered for information about Carlee’s disappearance and details leading to her whereabouts. The 25-year-old is described as being 5 feet, 4 inches tall and weighing 160 pounds. She was last seen wearing a black shirt, black pants, and a pair of white Nike shoes. Photos of Carlee can be viewed in the post below.