There is no requirement to arrest anyone for someone's death. There must be a reasonable cause for the arrest.
I think it is obvious to say that the TP was ridding high speed for his bike and himself to be thrown so far away, it does not look like at all that the van hit TP at high speed, since van had insignificant impact damages.
Safe to say that if TP bike was slow or normal speed it would had been only a very light accident, possibly no hurt.
The TP dept have to tell the public weather the TP was on a mission necessary to speed or not, from TP's duty dispatch record & from TP's bike dash camera.