Did Iver really need to use a ritual to identify the suspect?
In fact, he did not.
The moment he heard Captain Camus propose "copying the document," he had already identified the suspect.
The logic was very simple.
The document in Captain Camus's hands was not a "top-secret diplomatic letter" whose contents were unknown to everyone. It was "material evidence" whose contents everyone already knew—the very letter they had originally intercepted from the spy.
In other words, this was the "core evidence identifying Aleister." And nearly everyone knew it.
With Her Majesty the Queen having already warned them not to spread the matter any further, the Chief Secretary to the Naval Minister had nevertheless asked Captain Camus to copy it...
That had already exposed the Minister of the Navy's attitude.
Simply put, the attitude Her Majesty the Queen had shown the Round Table Hall was that she favored keeping the matter quiet. Thus, the letter was highly likely to "disappear by accident" or have its contents "replaced." The disappearance or destruction of the letter was the direction the royal family hoped to see.
Under those circumstances, going through official procedures and doing everything by the book, just in case... Whom that was actually meant to make things difficult for went without saying.
Moreover, Captain Camus had inadvertently mentioned that he was a "Hunter."
That was another important detail.
If this matter blew up and continued to ferment, what would ultimately happen?
Without a doubt, Captain Camus would be held responsible as the sole person accountable.
He would certainly argue his case, explaining that he truly had not seen anyone—he would repeatedly emphasize that, as a "Hunter," he had not seen anyone pass through the stairwell at any point.
In other words, either the thief had entered through the window without