The TikTok app has been criticized for encouraging some dangerous behavior, but now it may have helped saved a life.

A 16-year-old girl from North Carolina has been reunited with her family after police say she was taken across state lines by a 61-year-old man.

Deputies in Kentucky say motorists saw the girl giving a hand signal she learned on TikTok, indicating that she was she in danger.

"There was some people behind her that noticed that she was making hand gestures that signifies for 'I need help.' With them recognizing that signal, they notified 911," said Deputy Gilbert Acciardo.

Deputies say the girl had gone missing from her Asheville, North Carolina, home on Tuesday.

The girl was in a car going south on I-75 driven by James Herbert Brick.

The two were coming back from Ohio when someone in another car noticed the girl's signal.

"We don't know how long coming down the interstate from Ohio that she had been doing this to other motorists hoping that they would notice that she was in distress," said Acciardo.

The video that has spread around the world showing the hand gesture came from the Canadian Women's Foundation.

"I've been doing this work for a long time, where we talk about safety with survivors, with neighbors, like how you flip your light on, or do you have a certain code word if you text it to somebody that would say you need help or in danger, so there's always been these trends towards finding safety from community and I think this is just another platform to do so," said Darlene Thomas.

Thomas is executive director of Greenhouse 17, an advocacy group for abuse victims.

John Groshans, a school safety consultant and retired police officer from Floral Park, says he knows the hand signal well and is happy it's raising public awareness.

"It's good because teen girls and boys know what it is, and college students know what it is and we were very fortunate this other driver knew what the signal was to help this girl out," Groshans says. "He followed her for a long time."

Emerson Lucatorto, 16, is one of those teens who knows what the signal means.

"It's one of those things that you see or imagine and you think, 'I'm never going to have to use that, I'm never going to be in that situation,' and then you hear about someone using it and it being successful, it's a little more reassuring," Lucatorto says.

There are other TikTok videos that can help people out when they feel unsafe.

Bartenders at Trinity Bar and Restaurant in Floral Park know that customers ordering an "Angel Shot" feel unsafe.

"I think it makes everybody feel safer in general," says Debbie McCallum who works at Trinitary Bar and Restaurant. "You never want to go out and have something happen to you."

Officials say because a minor was taken across state lines, the FBI is taking over the abduction case against Brick.