I was frightened but I didn’t do anything

I was stopped by the police in Viale della Costituzione on 25/06/2019 sometime in the afternoon when I was going to the station to catch a bus. While I was walking I saw two police officers coming towards me, but the way they came for me made me think they suspected me of something and I was frightened but I didn’t do anything and they asked to see my ID. After the check they asked me again where I was going and I answered them politely, then they searched my rucksack and didn’t find anything so they let me go.