The FBI announced Tuesday it joined the search for a 14-year-old girl dressed only in pajamas and no shoes who vanished Sunday after she ventured out of her family’s cabin and into 50-degree weather to use the bathroom.

Katelynn Barlow was in Washington state's Big Lake area during a trip with her family from Florida when she disappeared around 9 p.m. Sunday, Q13Fox.com reported. Her uncle said he believed somebody lured her away from the cabin and kidnapped her.

Barlow had been staying with her aunt and uncle, who have primary custody of her.

The teen’s cellphone was found at a rest area near Interstate 5, about 32 miles away from where the family had been staying.

Juvenile Katelynn (Katie) Barlow last seen July 17 in Skagit County. Send tips to 360-428-3211. #SkagitCoSo pic.twitter.com/kCXEQ8zFmm — FBI Seattle (@FBISeattle) July 19, 2016

Barlow’s stepfather, Kevin O’Connor, says the teen is usually never without her cellphone. She was staying on the lake with her family for three weeks.

Jeff O’Connor, the teen’s uncle, told Q13 Fox that nothing unusual happened leading up to her disappearance.

“No one’s going to (run away), from Florida, in 50-degree weather wearing shorts, pajama shorts, and a tank top without any shoes. That’s why we feel this is an abduction case. Someone has come and taken a close family member from us and my niece is out there and I want her to please pick up the phone and call me,” O’Connor said.

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The Associated Press contributed to this report