I'm writing a scene from Severus Snape point of view that happens right after the first message "THE CHAMBER OF SECRETS HAS BEEN REOPENED. ENEMIES OF THE HEIR, BEWARE!" and I'm wondering - would Severus have know that Voldemort was the Heir was Slytherin?

I know that Lucius knew, correct? So wouldn't he have told others what happened in the Chamber last time - about Moaning Myrtle being killed. And what about Tom? He was very proud of the fact he was the Heir of Slytherin - you would think he'd allow his followers to know that? Also, I know it has Severus interrogating Harry, but that could just have been because he thought Harry was hiding something (and he was) or that Harry might be possessed by Voldemort - that is, if Severus knew.

I personally think he knew, but I'm not positive if that's canonically correct. What do you think?

Thanks in advance for your help.