(2) Where in the case of any murder referred to in subsection (1), (other than a murder referred to in paragraph (e)), 2 or more persons commit that murder, it shall be capital murder in the case of any of them who by his or her own act caused the death of, or inflicted or attempted to inflict grievous bodily harm on, the person murdered, or who himself or herself used violence on that person in the course or furtherance of an attack on that person; but the murder shall not be capital murder in the case of any other of the persons committing it.