People keep saying that but my grandfather lived to 99 years old and when he was 71 he was still relatively independent healthy and actively involved in the local cricket club. 71 isn't really that old.

What gets you is being old and unhealthy like Trump. I don't really follow US politics well enough to know how healthy this guy was but in photos he doesn't look particularly overweight so it is a little suspicious he suddenly died at 71 but not automatically evidence of an assassination plot, but suspicious enough that I think the police would want to do a cursory investigation.