Casey Miles was the first victim of Roger/Thinman.
Casey was taking selfies in her room when all of a sudden, she notices a strange figure standing behind her in one of her photos. She turns around and briefly sees Thinman standing behind her before the lights go out in her home. This frightens her and runs and hides in her closet. She is able to dial 911, but is only able to say that there is someone in her room, as the 911 operator begins tracing her call, a knife appears behind her and she is killed by Thinman.
Sam and Dean find out that Thinman is actually a busboy named Roger and Deputy Tom Norwood. Roger later reveals he killed Casey because she would not go out with him. Her death was later avenged when Roger was killed by Dean Winchester and Tom gets killed by Harry Spangler.