Someone broke in into my apartment and my roommate suspects me ?

My apartment was broken in and they took my roommate's cash and nothing else. I live with my girlfriend and I have lost the key but on that same day I decided to drop by during lunch and try to get a nap outside of my apartment in the staircase. We called the police and they checked the camera and they saw me going in and out( Before going inside my building there is a locked door that requires key and before that door there is another one that remains unlocked. I sat down there in between because I didnt want to sleep outside to the public's eye). My roommate is doubting me. Even though I am innocent can the police arrest me just because my roommate told the police he thinks I did it ? Don't they need a solid evidence of someone actually stealing to make conviction ?