The lead singer of the Boston rock band Morphine, Mark Sandman, died of a heart attack suffered onstage during a concert. collapsed onstage in front of several thousand spectators at a music festiv. Lemmy Kilmister, the lead singer of the heavy metal band Motörhead, died of a recently discovered cancer on Monday. and was at home, sitting in front of his favorite video game from The Rainbow. w. At the…