In a spin the vertical descent speed is relatively low and stabilises
In a developed spin the airspeed is low but the rate of descent is high (typically a few thousand feet a minute depending on type etc).
The only thing that may give some info could be the GPS if on, active and recording the flight path
Not so, I believe experienced investigators can glean much from the wreckage as to what the aircraft was doing at the time.
Stalling or spinning into the ground is invariably fatal although I am not saying this is what happened in this case.
Did many hours in the Cherokee 140 - great little a/c if flown within the limitations.
Thoughts and prayers with the bereaved.