I don't have an issue with staff who have access to internal systems not giving out info on a public forum, in fact it would seem foolish where the person can be identified, though equally I don't blame the OP for asking for it.
By reading the first post as:
"I'm curious about what has happened here, is there any more information anyone can share publicly?".
And giving an answer along the lines of:
"Not really. I can say that it happened at <location> and is being described internally as an 'operational incident', but there is nothing more I can share publicly [at the moment]."
The OP's query will have been answered as much as possible without revealing any non-public information, nobody getting aggressive or defensive and with no name-calling or accusations of whatever.
Posts like "I know but I'm not going to tell you" (whatever the reason for the not telling), and "I don't know but I wouldn't tell you even if I did" add absolutely nothing of value and (sometimes) just make the poster look childish.
If you don't know the answer, simply don't say anything.
If you know the answer but can't share it, and nobody else has communicated this already, just say that there is nothing you can say publicly. If someone has already said that, and there is nothing else you can add, simply don't say anything.