The soldiers kept watching me with their guns resting across their chests

In November 2018 I was stopped by two soldiers, those ones that patrol the city on public security duty. At the time I was in my third year at high school (evening classes) and my lessons were from 5pm to 10pm, sometimes a bit later if there was a lab session and I always went to school by bike because there are no buses after 8:30pm. The day they stopped me I'd had a lab session, and when it finished I came out of the school and got on my bike to go home. When I got to Via del Po, just after the bridge on the slope, I saw a patrol car overtake me and it didn't even cross my mind that they wanted to stop me, but after the slope and just before reaching the Japanese restaurant (All You Can Eat) I saw them again, coming back towards me on the other side of the road, but I just kept going and at a certain point they flashed their headlights at me twice, but I still didn't know what they wanted and then all of a sudden three soldiers jumped out of the car and started shouting at me "hey we told you to stop" and I answered that I hadn't understood their signalling and that that was why I hadn't done it and then they asked me where I was going and I answered politely that I was going home and that I was coming from school and then they asked me for my ID and so I gave them my ID and then two of the soldiers kept watching me with their guns resting across their chests as if they suspected I had something hidden on me but above all they kept eyeing my rucksack on my bike rack and started whispering to each other, but they didn't search me. The one in the car finished checking my ID and after 5 minutes in the cold he gave me my ID back and one of them said "You're OK! We stopped you because we thought perhaps you were like those others" and I asked them "what do you mean like those others?" but they didn't answer and that was all they said in the end.