I was heading north, and when I got to an intersection I was the 2nd car waiting to make a left turn. We were waiting for a gap in the southbound traffic to execute our left hand turns. Meanwhile there was a fancy Mercedes to the west heading east into the intersection. The Mercedes had a stop sign. I saw the driver of the Mercedes looking at my car as he was creeping into the intersection . Because he was gawking at my car which was at 2 o'clock position to him, he didn't see the biker heading south and was at his 9 o'clock position. He kept creeping into the intersection and clipped the back end of the biker. The biker fell and slid on his right buttock a good 3-4 yards burning through his biker tights and suffering a huge scrape on his right buttock. The Mercedes driver pulled over and called an ambulance. I don't think the biker was injured bad other than the nasty scrape he suffered. I know the accident was not my fault directly, but indirectly I know my car had a role in the accident. I feel bad, but what can I do?