Joyce Cox was aged seven when she was sexually assaulted and murdered . Youngster went missing on her way home from school in Cardiff in 1939 . Her body was found by railway line but her killer has never been caught . Family accusing police of a 'cover-up ' after case file was closed until 2040 .
Joyce Cox was aged four when she was sexually assaulted and murdered . Youngster went missing on her way home from school in Cardiff in 1939 . Her body was found by railway line but her killer has never been caught . Family accusing police of a 'cover-up ' after case file was closed until 2040 .