Watch a few of Justin "MR 17 5 40" Perry videos on Facebook, and you start to see a familiar scene play out.

There's Perry running up to a car, cellphone in hand. Inside the car is a man, anywhere from 30 to 50 years old, who bit on Perry's online persona of a 15-year-old girl.

"I'm the 15-year-old girl!" he yells.

Some offer pitiful protests, others get that deer-in-the-headlights look, but Perry is relentless, demanding they confess to wanting to meet a teenage girl.

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He'll even call their phone as they stand there, to prove he has their number.

Then he unleashes his catchphrase, "Remember my face! 'Cause everyone gonna know yours!"

By that time, the guy is usually inside his car, high-tailing it out of the camera shot, exhaust shooting out the back of his vehicle.

Vigilante or crusader?

For about a year, Perry, 32, has been staging his own online investigations into people he suspects are would-be pedophiles and then hosting live "gotcha" style videos on Facebook.

He chose the moniker, "MR 17 5 40," because 17540 is the ZIP code for his hometown of Leola, Lancaster County.

His videos have garnered lots of views and followers, but Perry says that's not why he does it.

"I'm here for one reason — to expose these guys, and that's it," he said.

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And that's usually the result of many of his broadcasts — inevitably, many of Perry's viewers figure out who the guy is and hound him on social media.

There was that one time he got the wrong guy. Perry made arrangements to meet a man outside a popular chain restaurant in Lancaster County, except there were two locations within a few miles of each other.

Perry went to the wrong one first. He approached a man seated on a bench and began to confront him and then realized he had the wrong guy.

"Bro, I am so sorry," he said to the man. "The guy was cool about it."

"'I respect what you're doing," the guy told him.

Not everyone is a fan, though. Some call him a "vigilante," others ask, "Who poses as a 15-year-old on the Internet?"

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But for Perry, the cause is worth the haters. He has a son, and his nephew has a daughter, so he shares the fears parents have in this digital society.

He knows how easy it is for kids, especially those who had a fight with mom or dad, to disappear with a stranger, he said.

"If I could prevent anybody from having to go through that, why not?" he said. "Someone's gotta do it."

'To Catch a Predator' 2.0?

Perry's pursuits of possible sexual predators brings to mind "To Catch a Predator," the popular NBC show that debuted in 2004.

In the series, hosted by Chris Hansen, suspected sexual predators would be lured to a house with the promise of meeting a 12- to 15-year-old, confronted by Hansen and then arrested by police.

In 2006, one of the suspects committed suicide, according to a 2017 story on TheMarshallProject.org.

That particular sting was set up in Murphy, Texas, and the man who killed himself was a prosecutor from a nearby county, according to the Associated Press in 2007.

The Murphy city manager who signed off on the sting was fired, and the district attorney declined to prosecute any of the suspects, as "many of the cases were tainted by the involvement of amateurs."

“'Certainly these people should be prosecuted to the full extent of the law, but the fact that this was all done for television cameras raises some questions,'” Murphy Mayor Bret Baldwin said in the AP story.

Tough for police to work with him

Perry's last video may have been his most productive, as it appears to have at least caught the eye of local law enforcement, although it's not clear if any prosecution will result.

In the video, Perry confronts a man from York County, who was recognized by a number of his former neighbors in Hellam Township who were watching Perry's stream.

"Everybody from the trailer park called the police," he said. "I wasn't even home yet, and I had all the guy's information" from people who had seen the video.

Hellam Township Police Chief Doug Pollock said the man Perry encountered lived in the township at one time and that his officers had dealt with him several times in domestic disputes.

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Pollock said the information Perry obtained is now in the hands of the York County District Attorney's Office.

"I understand why he's doing what he's doing," Pollock said of Perry. "Since he's not law enforcement and doesn't work under the guidelines we work under, it makes it tough to team up with him from a legal aspect."

'Should be left to law enforcement'

York County Chief Deputy Prosecutor Chuck Murphy said Monday that operations such as Perry's should be limited to professionals who are trained in investigations and can handle any possible violent situations.

"We would never encourage citizens to do this; these are situations that should be left to law enforcement," he said. "If you're putting yourself in these situations, confronting people, you never know what the outcome could be."

Murphy added that in the description for illegal contact with a minor, the Pennsylvania crime that could be leveled against someone in these situations, the victim must either be an actual minor or a law enforcement officer assuming the identity of a minor.

None of that deters Perry.

'That's go-time'

Ensnaring would-be pedophiles takes some time. And knowing what sites to log onto. And having a second cellphone, what he calls his "predator phone."

Perry sets up accounts, posing as a woman, but in the course of a conversation, tells the person he is 15. Immediately, that turns off some. But not all.

Some say they want to talk, or snuggle or drink alcohol.

"Once they start talking about sex or sending weird pictures and stuff ... that's go-time," he said. "I'm gonna go get 'em."

Perry sets up a meeting place, typically a well-lit parking lot at a convenience store or strip mall. Usually, his videos open with him staking out the meet-up place, waiting for the person to arrive.

The views and comments begin to accumulate.

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"I want to start doing this in Delaware man!!! Sickos everywhere!!!!!!!!!!" one viewer writes.

"Much respect and love to you for what you do," another writes.

As the would-be predator takes off, Perry turns the camera back to himself, where he thanks those watching and asks that they share the most recent video, then closes with another of his taglines.

"Keep 'em safe!"

Contact Ted Czech at 717-771-2033.