Secret Glarthir key. Oblivion

[360js]

Well while completing the humerous Paranoia quest, i managed to make a few hundred septems then got annoyed and snitched out Glarthir, robbed his dead body and stole his house key. While searching the inside of his house for loose gold, perhaps even a nice weapon i accedently found "Glarthirs Secret Key", located on a shelf in the basement. Does anyone know what this key opens?

[BurtonBoards25]

I don't know but i found it to i'm currently searching for somewhere to use it.. There aren't any secret areas in his house so i'm searching around it.