Or suffocate with snow..
Original wording was untraceable, though, that'd come up in the post-mortem, even maybe in an x-ray.
As to the article, not only is it from the Daily Mail, so has no real validity, either the article hasn't done its research (the Daily Mail not researching their stories?!? Never...) , or the guy was a total fucking moron..
Firstly, it says he had 251mg of caffeine PER LITRE of blood in his body. The human body has about 5 litres of blood in it. 251*5=1255mg of caffeine. Article says he paid £3.29 per 100mg, so the amount he took, I'm assuming over the course of a few seconds, was £41 worth, or around $66. He might as well have bought coke at that price...
However, another fact that makes me think the article is wrong somewhere, is that a normal, 250ml can of redbull contains 80mg of caffeine, about the same as a weak coffee. 1255/80=the equivalent of around 15.5 cups of weak coffee. (despite the article proclaiming it was equivalent to 70!) Very jittery, sure, and a bit of paranoia, but not lethal. I've had 20 cups of fairly strong coffee in the space of half an hour (don't ask!) and been fine by the afternoon. Pretty sure there was something else involved, á la the mephedrone news items.