Transcript for How ISIS uses the internet to target young Americans for recruitment: Part 3
Reporter: Tonight across America law enforcement is standing watch to thwart terrorism plots. In New York hundreds of surveillance cameras in times square alone. Officers not only with weapons, but radiation detectors too. How many radiation detectors? Thousands. Police officers wear on their belt that looks like a pager, radiation detection boats circling the ships as they come in. The radiation detection on aircraft. So that's every flight coming in and out of New York City. Reporter: John Miller deputy commissioner of intelligence and counterterrorism says ere are also biological detectors. Biowatch sampling the air and growing our cultures every day to see is there anthrax? Reporter: But underneath everything we are watching, is there something we cannot see. Beneath the cyber world we navigate a hidden swamp of hatred of all kinds. The encrypted web, which has legions of sites gathering places stoking anger. You can choose down one corridor racism. Here's some reality. 74% of the extremist-related killings in this country in the past 10 years have been carried out by right-wing extremists. Perspective from Oren Segal, director of the center for extremism at the anti-defamation league. Down another corridor he says, jihadist terror. 24% by those who are motivated by radical interpretations of Islam. Reporter: And in this corridor we can see phrases from the Koran their meaning twisted to serve a group of killers. There are also sites detailing how to be most effective when wielding knives or a truck against innocent people, including muslims. And most parents don't know that for kids all this is just a few clicks away. Most parents don't know. Uh in the past 3 ?? months, we're on now 450 plus ISIS telegram channels that have some level of English language content on it. They have a entire chat room-- to give you-- information on how to protect your computer from surveillance and the FBI. Reporter: Seamus Hughes of George Washington university leads a program and a group that tracks and analyzes extremists online. They just posted this, right now -- They just posted this about five minutes ago. Reporter: He says they're fast and up to date. Rising out of the swamp to exploit trending topics it's called #hijacking. This summer when we were all weighing in on game of thrones. So did ISIS supporters. One click taking you to an ISIS beheading that says "Then, they will be overcome." Reporter: This is haroon Ullah senior advisor to the state department and has written a book as a wakeup call. This is a battle we saw coming and weren't prepared for. They're still online every day? Every day. Working it every day? Yeah and I check it almost every day. They know how to fail fast. So they work on it, you know, they see what works and see if it doesn't work, they change it up. They have a "Game of thrones" kind of documentary/drama. They have music. Doing stuff visually entertaining and that's content war. So we ask him about online recruiting and the fact that 60% of those charged in ISIS inspired acts are Muslim. And the fear this has created in a lot of Americans. I grew up in a small rural America. Not dismissive of their fear? No. Because I think if I was in their position and I've seen the same information, I would be like what the heck is going on when you see things on TV. He's reviewed every case and they're mostly not about religion. Less than 10% of them were recruited solely based on religious dog ma. They have taken identity grievances and mapped it on to religion. If you have a machine 24/7 whose whole purpose is to recruit any child is vulnerable. Any child, any religion? Anyone is vulnerable. The former and first ever state department special representative to Muslim communities. She says never underestimate the power of this content. The idea that you would go to join someone who engages in beheadings, that you would suspend critical thinking about that? What's the difference in the generations? They can dismiss the vile and disgusting things they see because somehow it all fits into the narrative. I would say parents need to understand the tools that extremists use the same way they have made themselves away of how a sexual predator would be online. If you think smart successful kids are somehow immune to the trapped doors online, come with us to the federal transfer center in Oklahoma City. A jail where a guard is opening a door and on the other side there is someone who can answer questions about the story of two honor students from small Mississippi towns. One of them a cheerleader. The other a soccer player. His father a math teacher. Through the door mahammad dock la la. A young man who once had a bright future. Had you ever been arrested before? No, ma'am. Nothing? No, ma'am. I mean like car tickets. One of your friends was quoted saying he's the guy never in a bad mood. That is true. Yeah. He is the son of a Muslim father and a catholic mother who converted. He was a straight a student in graduate school studying psychology when he met his first real girl friend a superstar grew up going to church on Sundays, her dad a police officer, her mother a school principal. Super smart, intelligent, always very polite, not radical in any way. I know the kind of person that she is. Jaylen delshon young. She was so smart. The top of her class. Studying to be a doctor. Mahammad admits she was his first real relationship. What was it about her? Looks the one thing and then the next thing is intelligence really. So what happened? Jaelyn young has admitted in court she was the one who became so overwhelmed with her premed studies that anxiety and depression took hold and says she contemplated suicide. So she began to search for spiritual solace and looked at idealistic propaganda videos for ISIS. These videos are dangerously inspiration inspirational. If you're in a state of anger or state of depression, they really want to try to hook you in. Reporter: But it was Jaylen herself who says she was the first one drawn to fundamentalist Islam. She liked the strict rules of behavior, got in deeper and deeper and became convinced by ISIS propaganda that ISIS was misrepresented in the media. She began wearing an acobb. She wants her boyfriend to come and live with her in Syria. It made sense to you? He says in truth he just wanted to be with her. Are you saying you did this for love? Like blind love. But you knew they are a savage organization? We took that to be like more of a bias view from the media. Did you really believe that? You're a 4.0 average. I couldn't think straight. I feel like I had a depression but I hit it so well that I never asked anybody for help. When you're seeing beheadings of aide workers. I heard about them but I never did see the videos. It was all over the internet. I didn't go to many websites and she didn't go to many websites. YouTube is open outspace. He says he never knew that much about Islam. You were willing to kill Americans? No. It was more just like, you know, I want to help as much as I can. He told me he hoped maybe he could work in the pr department. Then one day two years ago after months of planning these two college students packed their bags and headed to the regional airport to travel to the middle East. What do they bring with them? Craft supplies. A scrap book. A bar of soap. Star burst minis and his Nintendo but their ISIS friends online were in fact under cover agents for the FBI who moved in and arrested them. At sentencing defense attorneys arguing these were just smart kids who had fallen into depressi depression, confusion. But the prosecutors argued not so fast. These are kids who knew what ISIS does and they were prepared to join up. Both of them expressed deep remorse but tonight Jaelyn young is spending 12 years in prison after prosecutors argue they instigated the idea. We asked to talk to her. She declined. Mahammad is now in for eight years. If they can reach the two of you, where is it going to stop? I don't think they're going to stop until we, you know, take care of them really.
This transcript has been automatically generated and may not be 100% accurate.