"A key with a picture of a joker stamped on it."
The Joker Key is a key item in Resident Evil Outbreak File #2.
If you have the Joker Key in your inventory, you can unlock simple locked doors. Can not be used on a desk or cabinet door.
If playing as Kevin Ryman, it can be found in "your" locker in the Night-Duty Room on all difficulties except Hard and Very Hard, In Very Hard it can be found in the Main hall, In Hard It can be found on the rooftop.