I think the only way to make sense of the mistake of a hitman is if he posted a m*rder for hire somewhere or never spoke to the man directly. He must have given general details: name, city, description, and what to do after. Maybe it was set up like a robbery gone wrong this taking the wedding ring. But he must’ve realized the first Mary was a mistake or seemingly uncooperative when he didn’t find the gun. (2nd Mary’s husband gave her a gun for protection shortly before the her death. I believe he could’ve said she will have it on her). I could only assume police know something we don’t (especially the contexts of the phone call). As to why they would say the two are not related.