Who Killed Mr. Tibbles?

Mine and NALs entry into GMC Jam 37 where the theme was "It Knows Something You Dont". A heinous crime has been committed in Spuddies Doll House. Mr. Tibbles has been MURDERED in COLD BLOOD! Spuddie saw the whole thing... but hes got a short attention span. Can you help him piece together the details of the crime?