Good evening. Police are adding patrols on the streets of an entire new york city neighborhood in response of an uptick of the so-called knock out game. The motives is not robbery but instead, the... See More
Good evening. Police are adding patrols on the streets of an entire new york city neighborhood in response of an uptick of the so-called knock out game. The motives is not robbery but instead, the thrill of pure violence and tonight for the first time, we're going to hear from a perpetrator. A 16-year-old girl cold docked in broad daylight. A man punched at a bus stop who later died. It's happening on sidewalks and on moving buses, too. Some in law enforcement belie this is part of a disturbing trend called the knock out game. Incidents ranging from london all the way to pennsylvania. Jamesed aleburger, a teacher and a popular local blues musician was walking home following a day at work. I walked that direction for nine years and I pick up a city newspaper from the rack on the street and was reading an article and proceeded to walk through the allalley, next thing i know I was answering questions. What happened next, a passing 15-year-old hauls off and punchesed alesberger who goes down hard, smashing his face into the concrete. It was violent but I didn't know what happened until I saw the film. When you came to, were you in a lot of pain? Yeah, I was in pain. I was confused. I was bloody. And eventually angry. My initial anger for that, i had no issues with anything. I loved teaching. I teach kids music. I teach kids english. It was very senseless and confusing. I questioned humanity. I do believe that people are intrinsically good. The worst part was seeing the kids laughing and leaving him for dead. I think the worst is when the kids laugh about it. The kids on my video walked away laughing and sneering. That is a sad thing. Now for the first time the young man who attackeded alesberger is speaking out exclusively tonight line. He did not want us to use his name or show his face. Take me back to that day and walk me through. Impulse of stupidity. I was just trying to show off for my friends. Do you feel guilty? Do you feel embarrassed? Of course. Of course. I feel guilty and embarrassed. Ashamed. This young man who is now 16 insists he had never heard of the knock out game when he attacked james a year ago but in recent days and weeks we have seen a spike in these kinds of attacks which some authorities believe may in fact be part of the game. What determines the size and scope of this game, if in fact it is happening to any great extent? This past friday, police charged one man for punching a 24-year-old jewish man. Police say there have been seven other similar attacks in this part of brooklyn including a 78-year-old woman and a 12-year-old boy. A medical researcher had a sucker punch to the face. A single blow and they fled after that. And a social worker was punched in the face while riding her bike. My whole head went flying to the side. It was a hard punch. There have been at least two deaths this year. This is surveillance video of teenagers running away after punching a man who then had a sei see sure and died. There is active debate about whether this is part of a game or whether it is just being linked together by the media. The teenagers we met said they do not play the game but had heard of it. They run to strangers and punch them in the face just for fun. I would never do that. Why would anyone want to knock somebody out? There's no reason. It's not a game. It's assault. It's violence. It's real. It's a crime. Psychologist. Violence for us is as american as apple pie. We have become desensitized to it. There are some individuals especially young individuals who may not have a large menu of exposure to the arts and sciences, to music. All they are getting is the violence and they react to that. In the recent new york city attacks, police believe the motive may be something more than a thirst for thrills. Anti-semitism. All eight victims have been jewish. Play knock out the jew. Late today, african-american community leaders spoke out. We are here together to collectively condemn the increasing violence connected to the knock out game. In the pittsburgh case, the young perpetrator says that race was not an issue. Was there any racial component? Not at all. There was nothing. I'm going to be completely honest. No matter who it was, they would have gotten hit. This is is a real economic issue where those who have nothing feel that they have nothing to lose. Not only do they get a thrill from doing something so horrific but then they get to watch it and then they get the positive reinforcement of people watching these videos and these kids are finding some sort of immortality by their bad behavior. What can be done here? One state legislator is proposing a first of its kind bill to charge kids who play this game as adults and impose sentences up to 25 years. Some say the media is compass baiting the problem. But others say parents can use it as a teaching moment. Talk to your kids about the images and make a special emphasis on the dangers not only to the victims, but to the perpetrators as well. The young man captured on this now infamous surveillance tape in pittsburgh was released a few months ago from a juvenile detention center where he spent nearly a year. I was bored. While inside his great grandfather with whom he was very close passed away. The young man says he is now trying to turn his life around. What are your feelings now about the victim? Apologetic. I'm ashamed that I did that. I'm embarrassed I did that. I wish I could take it back. I just feel like I owe him something. I'm grateful I'm alive. I can't say that enough. And it's good that he found something within him to make him feel a little bit guilty and hopefully it won't eat away at him forever that he can get on and be productive. As you know we are seeing all of these other cases of kids hauling off and punching people on the street. What would you say to any kid who thinks abdoing this? They do not know what they getting they self into. I wish I could tell every kid what I been through for like a quick second. I don't know. I don't want no part of that. The fact of knowing that you did that to somebody who didn't deserve it at all.
This transcript has been automatically generated and may not be 100% accurate.