A depressing affair

When I was coming back my apartment, I was called to stop by police officer. There were about 5 police officer there. They saw my bicycle's key and asked me to investigate it. They called me to stop because my bicycle's key was broken but I rode it. I told them that my bicycle was so old that its key rusted and my brother broke it. Although I told them that the bicycle was mine, they didn't believe me soon. My heart was heavy.