IAC can what it likes but disclosing this while its own investigation is still in progress could lead to him getting a better result than he deserves ie he might say my employer did not follow the rules so I am claiming unfair dismissal and win compensation.
They were "harassing"? The very conjecture that is to be investigated.
As an example, if I send a text to my girlfriend and co-worker that says "I'm gonna plow your fields tonight", it is a fact it was sent, was sexual but harassing? That is contextual.
Even if IAC has irrefutable evidence that it happened?