Complex sentence: Normally he would have wrapped the wire behind his neck, but he was unable to do so; the lines from the body bag appear to have become entangled with the light head, and the physical effort of trying to free himself led to his death.
Split into simpler sentences: Normally he would have wrapped the wire behind his neck, but was unable to do so. The lines from the body bag appear to have become entangled with the light head, and the physical effort of trying to free himself led to his death.