Motor accident: Bike hit the rear end of our car at a red signal

Hi, Recently, while my husband and I were travelling in our car, we were involved in an accident. We were on the road and about 50 meters ahead, we saw the traffic signal was red so we slowed down and as we approached the signal, we came to a halt. As we were waiting for the signal to change, my husband glanced at the rear view mirror and saw a bike coming down the lane towards us, speeding and not slowing down. About 3-4 seconds after that we heard a loud sound and felt an impact. I turned to see that the bike had hit the car on the left side of the rear bumper. Due to the impact the bike swerved onto the left lane where a public bus was oncoming. The bike hit the front of the bus and crashed. The biker ended up under the front right wheel of the bus. Ambulance and police arrived. The biker’s shin bone was completely demolished and he was rushed to the hospital. I would like to know if we would be held liable for anything. And if we are held liable, how are we to contest against it as this happened due to no fault of our own.