Sean parker of facebook and napster. What in heavens name possessed you . Maybe a hacker. A computer hack. Killer t cells like little commuters. A revolutionary therapy saving lives like hers. I found i was cancer free. Reborn . Yes, reborn. I think this billionaire is on to something. But first, Richard Engel with an nbc exclusive. I let my family down. I let my nation down. Why should i believe you . Hes the Young American that went from the ivy league to isis. He asked to help isis bring down planes. Why did he join, and why did he return . They got more brutal and brutal. You saw heads on a stick . Yeah. Tonight, a dark journey inside isis. You see madness in their eyes. That story right now on assignment. Good evening and welcome to on assignment. Im lester holt. Tonight we take you into the very heart of the terrorist world and for the first time, an american who joined isis in syria has returned to reveal the inr working of the terrorist group. He told his story exclusively to richard ingle. For the past 19 months, the u. S. Government has been hiding a valuable intelligence asset somewhere in new york. This week, they revealed him but only to us. Weve been asked to call him only mo and when fbi agents brought him out, he didnt look like a dangerous criminal but make no mistake, he pled guilty to two terrorism charges because in 2014 he spent five months in syria training with isis. Ive let my family down. Ive let my nation down. And ive let god down and i have a lot to make up for. So you in this interview and other places apologizing . Absolutely. Why should i believe you, that you really regretted it . One could say now youre facing a difficult situation and you have to say it was a big mistake. I mean, i took my steps on my own by going in. I also took a lot of steps on my own getting out, and im helping in every sense that i can to help rid the world of the evil that i saw. Mo is awaiting sentencing and hopes that cooperating with the government will buy him some leniency, a naturalized citizen, he came here from bangladesh when he was a baby and grew up in new york city. Did you grow up what you would call religiously extreme environment . No, not at all. What was it like to be a kid in your house . I dont imagine anything different from any other new yorker, at least a muslim new yorker because there is some religion involved, sure. I grew up playing basketball, going to school. Mos High School Paper published an essay praising super heroes including albert einstein, Winston Churchill and mr. Burke. He went to community college, made the deans list and caught the eye of a Colombia University recruiter. There you are Colombia University, a hard school to get in. Yeah, i was excited. Until a teacher in a class about islam played a provocative and controversial film called submission. Its a video about a woman in a birka with koran writing pointed on her and one of the most offensive things that made me feel alienated. Its an emotional thing and still bothers me. Do you think this was a turning point for you . Its c is. I became observant. Mo left columbia and for awhile drove a taxi through the streets of new york city. He was repelled by what he saw as temptation around him. He didnt take questions of faith and identity to his local mosque. Where do you look for these answers about islam . My research was mostly independent, what i thought was independent online. According to ali a former fbi agent that tracked islamic radicals, social media is isis main method for recruiting. They have the communication with them on social media and go to apps where it allows them to do peer to peer communication. Influenced what he saw online, mo began dreaming to go to syria where he believed a pure Islamic State is rising. Is it possible in the spring of 2014 that someone wouldnt have known what isis was all about, how brutal the group was . If you look back in the united states, for example, most of the experts that you are talking to will say hey, isis only kacares about establishing ca ca cale fite. He wasnt sure he wanted to leave until in 2014 the fbi came knocking. Why did the fbi come . They were wondering about my activity online. They followed your social media . Yeah. They thought it was suspicious . Yeah. They asked if i had any want to go. I did lie a little. I said im interested to go to syria. Two days later mo pretended to go to work but headed instead to the airport. This was a spur of the moment decision . It happened very fast. I bought the ticket and the night before i packed my bags, left a letter to my parents and. What did you say . I was planning to not come back, it was a farewell. He was able to board a flight to istanbul and make his way to orpha with foreign fighters. He made contact with isis over twitter and was soon driven with four other recruits to the border where they ran into trouble. We were caught by Turkish Border patrol. They beat the crap out of us. Punching you. Kicking a metal rod, the butts of their akas. And then . They told us to cross into syria. They told you to go into syria . Yeah. They stopped you, arrested you, beat you and said okay, get lost, go into syria . Yeah, and pointing a gun and i just did what i had to. I just ran. Mo soon reached a safe house and the first thing he was asked to do as a resident of the Islamic State was to fill out a form. It was just the guys took us separately and asked a bunch of backgroundtype questions. There was one box where they could say special skills. Uhhuh. On your form it said studied at Colombia University, has planned for taking down aircraft, could be useful. What is that . Well, i guess, thats how they wrote it. They said do you want to be a fighter, a fighter or a fighter . And you know, i was just really trying to think of an excuse not to be a fighter. But you were saying okay, dont use me as a fighter because im a terrorist mastermind . Huh . You said dont send me off to the front lines because i can be useful in other ways. Its shortsided but, you know, it seemed to me that it was, you know, save my skin. Two weeks after the initial processing, mo was sent to an islamic Training Camp like this one where he claims he was shocked by what the isis instructors were saying. What kinds of things were they telling you . Perspectives on, for instance, slave girls. It was something that they perpetrated and thought of as actual slavery and enslavement of just regular civilians and people. He says he was appalled but things were about to get much worse. He headed for military training next. A weapons class, a tactical class and there would be like a physical training class. What kind of weapons did you train on . They gave you an ak and they had you memorize it and everyone got three bullets a person. So they didnt want you to use too much ammunition. They were low on ammunition, i guess. Did they show you how to make bombs. They explained how to use it. The isis videos ive seen or anybody has seen are so brutal. All those videos came out a couple months after me being there. They just got more brutal and brutal in front of me. Its like a blood thirst, i guess. People just had a readiness for violence. The group was attracting violent people you think . Absolutely. Thats the bulk of the people going there. Did you see evidence of all the gore that we see in the isis propaganda . Towards the end, as things were getting more and more serious, i did see severed heads placed on spiked poles. You saw heads on a stick . Yeah. And what did you think . I just blocked it out. I tried to ignore it. You thought that this was going to be an islamic utopia you said is . Yes. You could see madness in their eyes. Youve been presenting yourself very much as a victim, someone that fell for their propaganda. Uhhuh. But you went and joined a group that is known the world over for its brutality. Im not saying im a victim. I know, ive seen the victims there. I dont support terrorism. I support islam. I like the idea of islam. Lots of people like islam and want to follow their religion who dont join International Terrorist group. Uhhuh. See, thats the trap. Very, very in line. He says he was seduced by isis, that he was effectively a victim. Do you buy that . I dont buy that. This is bologna, to be honest with you. There is an individual that went, joined isis and when he applied to join the organization in the form, he asked to help isis bring down planes. This is a person who went to join isis with terrorists intentions on his mind. Did you do any fighting . No, thank god, no. When did you decide that you were going to leave . One morning everyone was busy. They left me alone for an hour, and so i took that chance and i walked out. He found a sympathetic syrian that promised to help him sneak back across the border. I remember sitting in an internet cafe waiting for the guy to pick me up, and i was sitting there for over 12 hours. I was trying to email my parents. Saying im trying to come home, i made a terrible mistake but i may not survive. I may be caught and killed. I was shaking in my hands and thats what terror is and what evil is. As soon as he got to the turkish side, mo headed for the nearest u. S. Consulate. American agents escorted him all the way back to the states where he was promptly arrested by the fbi. Hes been in jail since and faces up to 25 years in prison. The government allowed him to speak to us hoping his story will detour other Young Americans from falling from isis pitch. I think i have a real message and thats the most important thing. The message is that Islamic State is not bringing islam to the world, and people need to know that, and i will say that until the day i die. How genuine the promise from an american that pledged his life for isis will be for a federal judge to decide. Coming up, love your pet . How about a spare set . When you see the dogs, do you think clones or puppys . Cloning your dog. So unbelievable and incredible. Why the man behind it all is breeding controversy. It will be very hard for the Scientific Community to get behind him. E result of overacti. Lyrica is believed to calm these nerves. For some, lyrica can significantly relieve fibromyalgia pain and improve function, so i feel better. Lyrica may cause serious allergic reactions or suicidal thoughts or actions. Tell your doctor right away if you have these, new or worsening depression, or unusual changes in mood or behavior. Or swelling, trouble breathing, rash, hives, blisters, muscle pain with fever, tired feeling, or blurry vision. 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Its a Manhattan Project for curing cancer with the immune system. And harry smith visits a science lab filled with cute little clones . Were the only place in the world where you can get one of these. Want one . I really think Small Business is tough. Its better to have friends out there. You have a great day. Appreciate it. It makes life on the road much easier. Now members get more savings with your rate at holidayinn. Com now members get more savings. Another antiwrinkle cream in no hurry to make anything happen. Neutrogena® rapid wrinkle repair works. In one week. With the. Fastest retinol formula. To visibly reduce wrinkles. Neutrogena®. Jurrassic park. Hollywoods version of cloning but they are real. There is one place you can buy a pet clone of your own. Harry smith traveled to asia. Were in south korea, a country proud of its Technology Based economy but we didnt come to seoul to look at the gadge gadgetry. Were here to see puppies. If you have a puppy in your home, you can get a clone here, yes, an exact genetic duplicate and if you think thats impressive, you ought to hear what they want to clone next. They traveled 5,000 miles from their home in the north of england to korea to see two little boxer pups. These pups are clones of lauras dog dillon and this is the only place in the world where you can get your pet dog cloned. Do they look like dillon . They look just like him. Richard is in construction. Laura helps with the business and walks dog. Richard says laura is dog mad. Dog mad in a good way. When you see the dogs, when you see the puppies, do you think clones or do you think puppies . Puppies i think. If you comprehend that i took these samples from a dog after he died and they come from that, its so unbelievable and incredible. Lauras 8yearold dog dillon died quite suddenly leaving her an emotional wreck. Would it be too much to say he was your best friend . He was my total best friend, yeah. I spent more time with dillon in the eight years than myself. In her grief, she remembered seeing a show on television about dog clones. I remember thinking i would love to do that with dillon but where would you get all that money from . Then the day after he died, he said what about this cloning thing . Cant we look into it. I said are you kidding me, its 65,000 pounds which is 100,000. You heard that right, the Sticker Price is 10 0, 000. Laura was there when they were born. The lab cloned 780 dogs for customers around the world including these two jack russell territories for this couple. Over here we have a pomerian and york shire territory. Clones . All clones. Here is clones for a client in china. Six of them all together . Yes. All clones . All clones. Just want to make sure. Here we have another clone for a client in india. Right. There you go. Looks like a happy dog. Yeah. A happy clone. The man behind all this dog cloning is dr. Hwang woosuk. In 2005 hwang cloned the first dog, the invention of the year. The year before hwang created a worldwide sensation when he claimed to have cloned a human embryo. A dramatic scientific first. Do you trust this guy . I cant trust him, no. Dr. Beth is a biologist and genius grant award. Dr. Hwang claimed to have cloned a human embryo and the whole world said what happened, what happened to the science . It turned out he hadnt actually cloned a human embryo and did some things that were not faverbly looked upon by the scientific and global community. Investigators found hwangs data on human cloning was fabricated and female lab workers were pressured into donating eggs. He lost his job and lost face. Hwang vowed he would spend the rest of his life repenting. Anyone that has lied very publicly and been found guilty of that, i think will be very hard for the Scientific Community to get behind him. But dr. Hwang has come roaring back building this foundation into an international cloning mega business and while we were welcomed at his lab, dr. Hwang turned down our request for an interview offering instead a proxy, researcher david kim. I think people have an idea that bizarre cloned animals are coming out of these dogs and they have two heads and three legs. That this is some frankenstein f factory. Cloning has been warped because of Science Fiction movies. We watched dr. Hwang perform the procedures necessary to clone the dog. He removes eggs from ovaries and needs a dna sample from a living or recently deceased animal. So you need that . Yeah. Cloning a dog or horse or in these pictures, a pig, the dna is lit up with dye and sucked out of the egg and the dna from the animal you want to clone replaces it and shoot in electricity and there. Not exactly biology 101. For laura and richard, it worked twice. I would literally could not believe it. She screamed and said its true. I thank god. Oh, no. The lab offered the second pup as a gift but there was a different kind of cost to producing a healthy clone, numerous surgical procedures on other wise ehealthy dog from th donor to surrogate. There are a lot of medical procedures for you to get your successful clone. Yeah. Is that all worth it . I mean, thats the part i do feel worse about knowing that these dogs are having to have unnecessary operation because im such a dog lover. Laura spent a lot of time at the lab and convinced the dogs here are treated humanly. There is the dow narcotnor o egg. Its predatory convincing someone if they give you 100,000, you can give them an identical copy of a beloved pet, its not fair. I got the genetic replica, looks like fido, right, barks like fido. There will be behaviors and physical traits and other aspects of this dog that will be identical to the dog that once lived, but its not the same dog. Identical twins are clones of each other but are different people. Some people see this program on playing on emotions of people like you grieving so desperately for the animal they lost. Yeah. Do you feel exploited at all in this process . No, not really. Anyway, probably is a way to deal with my grief and just to make me feel like there is still a part of him somewhere in this world, to feel like i have not fully lost him. But dr. Hwan