When Alastor Moody had lost his eye, he had commandeered the services of a most erudite Ravenclaw, Samuel H. Lyall, whom Moody mistrusted slightly less than average because Moody had refrained from reporting him as an unregistered werewolf; and he had paid Lyall to compile a list of every known magical eye, and every known hint to their location.

When Moody had gotten the list back, he hadn't bothered reading most of it; because at the top of the list was the Eye of Vance, dating back to an era before Hogwarts, and currently in the possession of a powerful Dark Wizard ruling over some tiny forgotten hellhole that wasn't in Britain or anywhere else he'd have to worry about silly rules.

That was how Alastor Moody had lost his left foot and acquired the Eye of Vance, and how the oppressed souls of Urulat had been liberated for a period of around two weeks before another Dark Wizard moved in on the power vacuum.

He'd considered going after the Left Foot of Vance next, but had decided against it after he realized that would be just what they were expecting.

Apparently he was unable to obtain the Eye of Vance secretly. Besides, the presence of Moody plus the death of a dark wizard known to possess the Eye of Vance plus the missing Eye of Vance is enough to conclude Moody has the Eye.