Case law and forensic science evolution changes everything from 10 or 12 years ago.  This wasn't just an accident.  It was a fatality, vehicular assault, attempted murder, assault with a deadly weapon, discharging a firearm in the MOA, and that's just the felonies.  Anytime there is a fatality in an accident the work of police is significant.  You have grieving family, friends, insurance companies looking to fix responsibility, life insurance policies, civil and criminal suites.  Police do not want to stand in the rain at 0300 because of things like this.  They get called out of bed for it.  Belaboring the investigation and not clearing the road because people have to go to work is silly at best.