The mail carrier had already delivered the mail by the time I left for school this morning.
I ought to change that sentence into passive. Here is my attempt:
The mail had been already delivered by the mail carrier by the time I left for school this morning.
Is it correct? I'm not entirely sure how to put something (already, always, etc) in perfect tenses. I've read about the difference "have always been" and "have been always" that can be read here. And one of the answer said both are gramatically correct depend on a context. So, is it true in my case too? Which context I should consider?
I will provide another example:
I read about a hunter who had been accidentally killed by another hunter.
I read about a hunter who had accidentally been killed by another hunter.