I know it's easy to try and pin this on a 7 stone mother in a psychotic rage which apparently made her powerful enough to beat and overcome her 6 foot 4 inch father and also kill her two boys but I'm not buying that.
It is amazing what people can do when they are under extreme stress. I have a friend in the fire service (retired now) and he says there is nothing stronger than a mother outside a burning building who believes her children are inside, they assign the two biggest strongest fire fighters to stop her.
Loving mothers do kill their children, Andrea Yates was a loving mother who killed her children because her mental health and religious views combined to make her think they couldn't get into heaven if they 'stumbled' so killed them to save their souls.
OK that doesn't make Bamber innocent.
The farm house wasn't preserved as a crime scene, in fact it was used for some sort of training so had numerous people traipsing through.
That must have had an impact on the evidence and its collection. I think it was weeks after the deaths when they did start to process it as a crime.
She could have snapped but I don't see how she could have overpowered her much bigger, much stronger father, without getting any injuries herself, and kill several people with a shotgun she wasn't experienced with using without getting any gun residue on herself or her clothes
See my point above for the strength, and it wasn't a shotgun. it was a gun used to shoot rabbits, a rifle.
As for Bamber's innocence or guilt, I don't know.