When the guy met up with Gwin he thought he was Rsnail. The guy knew where he was going. He decided that in another day. He will make rsnail (Gwin Really) to go inside the bag of puffle food. He put the puffle inside the bag. Gwin did not know this and when he went to get the puffle food he found the puffle. He went inside and he found himself trapped. The murderer went and wanted to put Gwin inside the water at the Mine Shack. He missed and Gwin fell in the snow. The murderer took Gwin's hat assuming it was rsnail's and he found himself victory. The murderer is the one with the hat.
It is Mateo

The killer is Killer Mateo might be a worker but who knows! Look out for rsnails hat! Let me know!