"Friends"?

I was walking back through the streets at night and I saw two teenage boys in a yard / garden area. They were kind of scuffling but standing up. I was like, hmmm, and I gave them a look but kept my distance. I actually thought I could hear a whisper, like "I'm so scared." And then they ran up the street along side me, past me. They ran back down and one yelled at me, "He's sexually harrassing me. Help me." I stopped and looked at them, as they kept running down the street. I really felt very unprepared. I also wondered if it was just a joke. I thought of teenage boys in my high school, joking about stuff like that. But I decided to act like it was not a joke to me. I managed to yell, "Well, then STOP IT!" And the one who hadn't yelled said to the one who had, "I'm not touching you!" But I watched them and they started to walk apart and then they were walking with a big space between each other, one walking behind the other. And I thought, if the one who yelled wants to get away, why is he still following that guy down the street? But I also thought, it could be complicated. Maybe they are "friends." To be honest, I instinctively did not want to be around them. But after they disappeared, I walked down a block to see if I could see them. Would I yell something else if I did? How involved did I want to get? It was not a well-lit street. But I did not see them. This was the first time something like that happened to me, and especially when walking home at night. I  know that it would be good to remember that teenage boys can get harrassed and I know it will be less of a surprise to me if it happens again.