An app that's widely available and free for download has caught the attention of federal investigators.

The app “Yellow” is known as "Tinder for kids," and critics said it's a playground for child predators. It works through SnapChat and markets itself as a way to make new friends, but there is virtually nothing stopping a child predator from using the app and pretending to be a teenager to meet other teens.

"When I looked at it, I realized it's just another ploy for these child predators to get onto to become friends with my son," said Heidi Pritchard, a mother who caught her 15-year-old son trying to download Yellow.

"When I first told him about the dangers I got the eye roll. But once he read the stories, he realized it can be scary," Pritchard said.

>> Read more trending news  

FBI agents in the Pittsburgh office said predators are using apps more than ever.

When you sign up for a new account in the Yellow app, it asks for your birth date, including the year. There's nothing in the step to prevent an adult or a predator from creating a fake birth date, and saying they're 13, 14, 15 or 16, then immediately getting matched up with teenagers to chat or exchange pictures.

"Some of these guys with a little bit of cyber background can extract data from these pictures and actually get the geographical location of where the picture was taken," said FBI Agent John Orlando.

The app reports having 7 million users and is very popular overseas. In the United Kingdom, one of the largest child advocacy groups is demanding Yellow create an age verification system.

In Western Pennsylvania, school officials said battles against apps like Yellow are never-ending.

"There's no parent or educator or a decent person in their right mind who would think that's a good idea. But developers will do it as long as there's a market," said Aaron Skirbin, principal at South Fayette.

Skirbin said the best way to protect children is by giving them information.

"Education has to start before high school. Education has to start the moment a parent chooses to put a device in a kid’s hand," he said.

Pritchard has Apple's "Family Share Plan,” which means when one of her children tries to download an app -- whether it's free or paid -- she gets a notification and has to approve it.

"I don't want my kids to be afraid of the world, but I want them to know that there are scary situations out there," Pritchard said.