I tie a lot of knots. I don't know of one where the tag end finishes at the top like that, but the Kreh someone linked a minute ago is one I tie for fishing all the time, and I would tie it in a rope if I didn't want a loop to close. There are so many knots, it's hard to know for sure, but lots of knots finish in coils, and they're often layered like that. Doesn't make it a noose, but that pic I shared in the tweet certainly looks like one. The thing which would make it a noose or not is whether it slips. If it doesn't slip, it's not a noose. I'm guessing it doesn't slip, and that's why the FBI would say "fashioned like a noose" over "it was a noose."