The civil police have primacy in all matters. Usually however they cede that to the military police. They usually only retain primacy when there may be criminal issues - not for one minute suggesting that is the case here but the Puma at Catterick and the GR4 flight test from Marham are examples where the investigation revealed possible criminal issues and so civil police maintained primacy.
At this stage it is wrong to speculate and comment with ill informed data - it will ony serve to upset and annoy.
Thoughts and prayers with you, the team, friends who know you and your family.