"There it was in plain sight," Joseph Lyons told WGHP. "A pedophile just exposing himself to my little girl. She didn't deserve the pictures that she got."
She was using the app "Say Hi." Lyons said he saw a video of a man named Scott molesting a little girl. He says he will never get that image out of his head. Even more troubling, he noticed the man was trying to meet up with his stepdaughter.
Lyons got angry but had the presence of mind to call Thomasville police.
"They took it as personally as I did," Lyons said. "They made us feel comfortable, they asked the right questions."
Sgt. Steve Currie and his team passed the tablet along to Homeland Security.
"You're dealing with people that can be as close as down the street or across the country and unfortunately with social media you're inviting a lot of people in your home that you don't know," Currie said.
Within the next day, they arrested Scott Trader in south Florida. Police say he was found with multiple devices and hard drives filled with child porn. A federal judge sentenced Trader to life in prison last week on child pornography charges. Investigators say his arrest led to more young victims across the country.
"I couldn't have asked if I set a timetable for them to have any more of a productive response," Currie said.
For Lyons, he's trying to use this as a learning experience and push parents to check their kid's devices.
"You don't know what's out there," Lyons said. "Don't ever feel scared to call in an event like this."