Firstly, it is with profound regret that we learn of the 4-fatal mid-air collision in Arizona. Needless to say a melancholic haze descends on the pprune community every time there is an accident and loss of life.
The pilot to pilot audio comm has been posted on the ABC news site. One pilot is heard reporting his position as directly under the other helicopter, then there is brief confusion as to who is on top of who, then the pilot goes back to live reporting of the chase (the pilot serves a dual role, that of pilot and that of live to air reporter). Then a few seconds later there is the mid-air collision, an expletive, and the audio clip stops.
From initial listening of the audio it is not apparent that the situational awareness confusion was resolved before the pilot went back to reporting what was unfolding on the ground.
It is difficult to understand how the collision unfolded when at least one pilot was in sight of the other, and both pilots knew of their close proximity to another aircraft, al-be-it some confusion as to who was positioned on top of who. Hopefully all will be revealed at the subsequent investigation.