Anyone in a car has the upper hand versus someone on a bicycle.
And I highly suspect that the driver started IT.
I'm not saying that's how it went down but it's almost always like this. Since when do bicyclists go around harassing people in cars.
Of course we have no idea what transpired before this but I will suspect driver starts it, bicyclist with a bad attitude on that day decided to finish it.
And mind you the bicyclist likely told police that he punched him in the face. There has to be a real good reason for this.
Just look for a white BMW with front end damage with possible paint transfer from the dumpster he hit.
This sounds like a job for NCIS LA.