App helps parents uncover son's alleged abuser

The student's parents used an app called Sentry that caught repeated use of the word "baby" in the student's messages with his teacher, who's accused of sexually assaulting him. SUBSCRIBE to ABC NEWS: https://www.youtube.com/ABCNews/ Watch More on http://abcnews.go.com/ LIKE ABC News on FACEBOOK https://www.facebook.com/abcnews FOLLOW ABC News on TWITTER: https://twitter.com/abc GOOD MORNING AMERICA'S HOMEPAGE: https://www.goodmorningamerica.com/