By Chris Hansen, Dateline correspondent

For an upcoming investigation into online sex predators, we went to Murphy, Texas— a bedroom community outside of Dallas and rigged a house with hidden cameras inside and out. And as always it wasn't long before men came to the door looking for a young teen home alone. 

54-year-old Stanley Kendall met a boy online who told him he was 13. He was really chatting with a decoy from Perverted-Justice. 

Online, Kendall told the decoy he wanted to teach the inexperienced boy different sex acts and sent a picture of his genitals.

Incredibly, it turns out he's a school teacher. When confronted, Kendall told us he teaches math at a Dallas Middle School. He also says even though he talked about teaching the boy all about sex, it never would have gone that far.

Outside, officers from the Murphy police department are waiting to arrest him. He's charged with soliciting a minor online  and is being held on $50,000 bail.

In Texas, the topic of Internet predators has become a highly charged political issue. The Attorney General and the lieutenant governor both used cracking down on child sex predators as a central campaign issue.

It's a felony in Texas to solicit a minor for sex over the Internet—even if the suspect never leaves his house and never actually attempts to meet the minor. 

"I guess that's what I like so much about the way Texas law is written: the fact that the meeting does not have to occur so we can still make a case out of it," says Murphy Police Chief William Myrick.

That was the case when a decoy from Perverted-Justice started getting messages from a man who we learned was an assistant district attorney from a nearby county. He was a 56-year-old named Louis William Conradt Jr., screenname "inxs00." He chatted graphically about sex with a Perverted-Justice volunteer pretending to be a 13-year-old boy and he sent pornographic pictures to the decoy. He talked about coming over to the undercover house, but in the end never did. And as far as we know, he never knew Dateline was in the area.

The Murphy police obtained an arrest warrant for Conradt and did something we've not seen before: They contacted the local authorities in Conradt's town and knocked on his door.

Conradt didn't answer, but police said there were signs he was still inside.  So a tactical team was called in. The officers lined up in formation then broke through the back door. But before they could make the arrest the assistant D.A. pulled out a gun and pointed at his head. Lieutenant Adana Barber was there.

"As they made entry they confronted the subject, I believe he was in the hallway... he told them he wasn't going to hurt them and then shot himself in the head," says Barber.

Officers performed CPR and Conradt was airlifted to Parkland Memorial Hospital in Dallas where he later died.

As is standard procedure, police are investigating the handling of this case.

Officers also seized the computers at Louis William Conradt's house.

Dateline will continue to report on new developments, and on the rest of our investigation in Murphy, Texas.

by Allan Maraynes, Dateline Senior producer

As of this writing, our 'To Catch a Predator' team has visited 6 states, 8 locations, and has broadcast almost 15 hours. What's been eye opening to all of us is, especially recently, is that many of those who are now coming to the undercover houses have actually seen our broadcasts. They actually worry out loud that the person on the other end might be part of a Dateline investigation.

And still they come. 

They finish their sexually graphic chats online with individuals clearly identified as underage, they get in their cars, sometimes driving hours, and most shocking of all, they open the door to a stranger's home and walk in!

You tell me. Is there a problem here?  If so, what does it tell us? 

What I do know is Dateline didn't discover the problem. Everyone knows that the Internet has some very bad neighborhoods; ones we warn our children to stay away from. For years, law enforcement has conducted stings of those who try to use the Internet to exploit sex, either involving children, or simply selling pornography.

What we did do was find a way to illustrate the problem. 

When we decided to observe what Perverted-Justice does, I knew it would be interesting to see, in real time, how online predators communicate with someone they believe is a minor.  But I wondered if one of them would actually be brazen enough to leave the cocoon of cyberspace, get in his car, and try to meet the "child." And if they did show up at a house, would they run?

I asked if we could actually get one of them to come inside a house.  If we did, could we get him to talk?

What I was looking for was person-to-person conversation. Some sustained communication that might shed some light on how online predators think.  How would they explain what they do and why they do it?

I was the first to think this was a long shot.  Why would an online predator stop to chat once he knew he had stepped into a very different situation than the one he'd expected?

Producer Lynn Keller along with our hidden camera team went to work. A house was rented.  Multiple cameras were installed.  The Perverted-Justice volunteers (posing as minors) went into the chat rooms were almost immediately approached by adults for sex, and proceeded to "invite" those adults to our house. 

Then our team waited. What happened next was astounding. When Correspondent Chris Hansen greeted these men instead of a young child, most froze like the proverbial deer in the headlights. Except these deer were talking.  And talking… and talking.

What resulted was an incredible glimpse into the mind of the predator. What I am convinced Dateline has done for the first time, is illustrate that these predators don't look like snakes, or worms, or whatever creatures run for cover when rocks are turned over. 

These are often normal, average, next door neighbors. Respected members of society.  Teachers, doctors, clergymen. That's what I think has triggered it all.  And this is why  I truly believe the Dateline series has made us pay much more attention to the problem.

When we began our investigation we had no idea it would evolve into a series of broadcasts.  But since these men continue to arrive at our undercover houses, all looking for sex with a minor, we're still asking what it means?  Is it merely an Internet problem?  Or does it say something about deeper social ill that needs to be explored?

We're still trying to figure it out, and we hope our viewers are trying to learn along with us.