If I knew the lead character in this (who was acquitted of murder thanks to a photo that proved the lead character was innocent [after being wrongly jailed], and never charged/tried for any sex offences involving any of her pupils), I’d treat her with kindness and respect.
It seems quite unbelievable how the other characters are ill-treating her - as if she’d been proven to be guilty!!
It’s also odd that (as at the end of E1), there is no explanation as to why the photo that cleared her was not produced at her original trial.
I'd figured out it was Sam, but not for the reason that it turned out to be. I thought that he'd believed the rumours about Sally and Matty, and sought to put a stop to it.