WAS A TEENAGE GIRL LURED TO HER DEATH WITH A FEW KEYSTROKES ON A SMARTPHONE APP? "48 HOURS" INVESTIGATES IN "KILLER APP," SATURDAY, SEPT. 24

Nicole Lovell, 13, signed onto the chat app Kik looking for a friend. Instead, she may have found her killer. With a few swipes on her smartphone, Lovell became a victim of the occasionally dangerous world of anonymous online friending, where predators hunt for victims by using fake names and profiles.

Peter Van Sant and 48 HOURS investigate the murder of Nicole Lovell and the hidden dangers of connecting online with strangers in "Killer App," the 29th season premiere, to be broadcast Saturday, Sept. 24 (10:00 PM ET/PT) on the CBS Television Network. "Killer App" tells the story of two families whose daughters got involved in online relationships that became a matter of life or death. It's a story that will resonate with millennials, teenagers and parents, who, thanks to so-called "parent proof" platforms, often don't know what their kids are doing on their phones, laptops, tablets or computers until something goes terribly wrong.

"It's no longer a situation where you worry about your child meeting a stranger in the park," says Pamela Casey, District Attorney in Blount County, Ala. "You really need to worry about the stranger your child's meeting on the phone you gave them for Christmas. This is the new crime of our time."

Indeed, Branden Syrotchen found out firsthand when he caught on that his daughter, 15, was communicating online with a 30-year-old man, and that the two were planning to run away that night. In a heartbeat, what seemed to be the quintessential American family was at risk of being torn apart - or worse. Syrotchen and his wife, Brandy, took the matter into their own hands with a shocking result.

"A predator will drive across the state," Casey says. "Once they meet someone on an app they will go to all lengths to get these kids."

How easy is it? Van Sant talks with a 38-year-old convicted predator, who demonstrates how easy it is to set up a fake profile on the Kik chat app and send out an anonymous message looking for teenage girls. It takes just 44 seconds for the first response to arrive, and he gets another just three minutes later. "In two days max, I could have her sending me nude pictures," the predator says. "Once you make them happy, you've got their heart. Once you've got their heart, everything else follows."

It's a hard lesson that Nicole Lovell's family found out too late. She was stabbed to death, and her body was dumped in the woods, 90 miles away from her home in Virginia.

After refusing 48 HOURS' requests for an on-camera interview, Van Sant tracks down Kik founder Ted Livingston at a conference. "What personal responsibility do you have to make sure that children who use the Kik app are safe?" Van Sant asks.

"I think I have a huge responsibility," Livingston says. Livingston also compares the use of Kik to Facebook and Instagram. "Kids are going to use a messenger," Livingston says. "If we were to shut down Kik tomorrow, there'll be 10 right behind it."

48 HOURS: "Killer App" is produced by Josh Yager. Emily Wichick is the field producer. Gabriella Demirdjian is the associate producer. Michael McHugh is the producer-editor. Marcus Balsam and Mike Baluzy are the editors. Peter Schweitzer is the senior producer. Susan Zirinsky is the senior executive producer.

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