Have you asked Murat to publicly comment about this before throwing a conundrum in town square? If not, go do that first.
Is it a must?
You want to open an accusation or inquiry about a person, then yes it's a must to pm that user and let them defend themselves. You don't hold a trial in court and not inform a defendant!!!
He may or may not respond (likely not) but you have to at least PM him to give him the option.