The cause of his death is still unknown, and without being told, Logan and Daphne, as well as the hunters know fully well that it was by a supernatural creature, they just don't know which one.
The banshee might have a clue, but there was no certainty that she recalled anything of what she saw.
Logan's Aunt's husband left some hours after keeping watch on Logan. He was very suspicious of him because he recalled the hesitation in the eyes of the werewolf when it attacked him. It was almost as if it didn't want to attack him.
Not just that, but he found Logan's trips to be suspicious. One of the things that removed Logan from his list was when he tried to use wolfsbane in the house a few days ago. Logan didn't have any reactions whatsoever, it was almost as if he didn't know of it.
He still doesn't know of Logan's immunity to wolfsbane since the few who know of it are dead.
When Logan noticed he was gone, he came out with Castiel.
