Fullstop inside or outside bracket

I need some info re dialogue/interviews

Eg. "But they are Susie's shorts". [Greg still believes Susie is a boy]



Obviously the info in square brackets is a separate sentence. (Does this mean the full stop stays inside the bracket?)

Or - although the info in brackets can be considered a separate sentence, its content relates to the dialogue, therefore would you place the full stop outside the bracket.



Eg. "His eyes are green". [He points to his friend's green eyes]

In this example should the fullstop be placed inside or outside the bracket?



Please could you answer these questions and explain why. Could you also give me some examples using dialogue/interviews etc.

Thank you

Sarah Sills