The presumption it is them. The presumption can be rebutted only by clear and convincing evidence that it is not them.
It’s OK to presume it is them because usually it is and the presumption may be rebutted.
‘Assumption’ is NOT our friend. Jumping to conclusions like that makes us, and our site look like a bunch of racists. Too many of us do it all the time here. I’ve been guilty of it myself on occasion. I think it does us a lot more harm than anything.
I’m going cool it, myself. Nothing personal so don’t take it that way.