Investigation
How it is done: the United States and Ukraine
Two systems, two sets of published rules, and what a member of the association should take from each.
Principles from published manuals, not procedure. What has to be done at a scene is set by the law of the country you are standing in and by the orders of the service you belong to; where those differ from this, they govern.
Lessons
This material is education, not certification, and it does not replace accredited professional or medical training. It describes how the association works; it is not legal advice and confers no powers.