DV.
People not connected with the units involved, free from any pressure that senior officers might be applying, in order to ensure that all possibilities were considered. I was Air member for a BOI in the past; I lived and breathed the investigation, but at each stage there was an independent there, to challenge our assumptions and ensure we considered all eventualities.Nowadays that is the role of the DAIB, but they have just formalised the independence; it always existed.
Which you would know if you had ever served on a BOI or an SI, but you haven’t, have you Jimmy? You think you know how it works but you don’t. Because you’ve been out of it for so long that you only have experience of pouring over what is available on line, making up those conspiracy theories in your silly little head, and behaving for all the world like some weird amateur ambulance chaser. Do yourself a favour and give it a rest eh?