My 5-year-old son was the victim of "knockout" and we didn't even realize it.Weeks ago, just after dropping my older son off at school, and right before my younger one was to be dropped off at his school, we were walking on a New York City sidewalk when my son, who was holding my hand, stumbled. He didn't fall to the ground but his entire body jerked in a way that I knew he didn't just trip. I was baffled. He used to be a little clumsy, but not this time. Something bizarre happened. I turned around to see two high school aged girls, about 15-years-old, glaring at me. We walked into a Starbucks and I kept turning to look at the girls. I didn't yet know about the game of knockout but wondered what had happened. My son then said, "Mom, I think those girls hit me in the head." Without thinking we ran outside and I began to yell, "What did you do to my son? Why would you hit my boy?" They gave me angry responses and my son and I walked back into Starbucks.It didn't occur to me to call the cops. It was sort of a moment of disbelief. I remember thinking how bizarre it was and continued to ask my son what happened. I must have asked too many times, or he sensed my concern, so that he then said, "Well maybe I tripped." We both knew he didn't trip.Weeks later, after dropping my son off at school, I saw the same girls. So I decided to follow them. I don't know why. And then I saw the unbelievable -- I witnessed them do it to someone else. They walked next to each other, quite close, and then, as an elderly woman was walking in front of them, they slightly separated, as if to make room, but they don't make any room at all. They banged right into the woman causing her to fall. I continued to follow while calling 911. As the operator answered, I saw them do it a second time. And instead of keeping quiet, I couldn't help myself, I began to scream at them. "What is wrong with you? You did this to my 5-year-old son! What are you doing? I'm calling the cops." And they started to run. And I started to follow. Not too brilliant on my part. Why would I actually tell them I'm calling the cops? It was like an out-of-body experience. I couldn't help it and I actually began chasing them until the 911 operator told me to stop because I was putting myself in danger.Just last week, my older son told me he saw a story on the news about gangs playing a game called knockout. It was then I realized exactly what happened to my son that day.I now had a mission and it was to get these girls off the streets. I was now pretty sure I knew they were in the same spot at the same time each day. When someone hurts your child you have to take action.But just as important to me is what would their moms think? Wouldn't they want to know? Maybe by taking action I could help change these girls lives before they continue on this dangerous path.So today, I did my part. For them and me. As we were in the midst of our morning routine, I spotted them. I waited in Starbucks while calling 911. I had to call four times and wait 21 minutes before help arrived. I paced back and forth and walked and kept an eye on them in McDonald's just two doors down. I made it my mom mission to keep our neighborhood free of knockout. When the cops finally arrived, I was given the third degree, as if I was the aggressor. I was told I could be charged with harassment for following them. Bring it on, NYC. If I have to be arrested to keep my area safe, to scare these girls and make them stop, then so be it. The cops walked up to the girls and I immediately saw the scared looks on their faces. They saw me too. It was hard for me to hear what they were saying, but I heard mumblings that they knew who I was and knew I had followed them. The cops took their ID's and I learned they are high school students at a nearby school.After 45 minutes, I was finally able to convince the cops to let me file a report.I was told that I couldn't just make an accusation. I was told that I should have called 911 at the time of the incident. I was told that I couldn't file because my son wasn't injured. I was told that I couldn't file because I didn't see it happen to my son. I was finally able to file when the sergeant arrived and allowed me to file because my son told me he was hit.I'm not optimistic that anything further will happen. But I did my part. I hope the cops follow through and speak to their school and to their parents. As for me, I will now have to change our morning routine because, unfortunately for me, they now know me and know that I reported them. I just hope it can turn out well for them. If their mothers don't care, this one does.(huffingtonpost.com)ANN.Az