Is this sentence correct?

[HarryONeil]

Well, I've come across this sentence:

She said she'd been blocked on social media. was he the one who did it?

I wonder why the person who wrote this used Simple Past. I'd say like this, if I were the one who wrote it.

[...] Had been he the one who had doneit?

[Alan]

Your suggested rephrasing, while technically justifiable, would be considered cumbersome/stylistically infelicitous by most contemporary speakers, hence substitution of the past simple here (where there is no danger of chronological ambiguity).