CHARLOTTE, N.C. -- After 84 children were saved from sex slavery by the FBI, investigators are urging parents to be aware of their children’s social media accounts.

One online trend among teens, called "Finsta," is causing some concern.

The term, Finsta stands for "fake Instagram."

“That's the new world for teenagers where they have a second Instagram account but is there a very real unfiltered self,” said Laura Tierney, president and founder of The Social Institute.

“I think it's a concern for every parent, the idea that your child is using an account that they want to keep private from you.”

The FBI and local law enforcement agents who participated in Operation Cross Country found many traffickers found their victims online.

“I can tell you there is a problem here in Charlotte,” a CMPD spokesperson said. “If we're not in-tune and looking through those and knowing what our kids are doing, then anyone can reach them and talk them into something.”

Tierney suggests asking your children outright if they have a Finsta, also known as a spam account.

“Coach your child through 'what ifs,'” she said. “What would you do if someone you've never met in real life reached out to you on your Finsta?”