Martin, I was only asking a friend last week if the actual cause had been made official. According to what I've been told so far there were three riders, one behind the other, Kirk, Mark Atchison and Jamie Stauffer and a fourth rider came around, apparently just missing two but T boning Kirk. Whether or not it was a throttle sticking or rider error I honestly don't know. This rider was experienced, though. The accident happened during a Formula-Xtreme/Australian Superbike meeting in Queensland. Very sad indeed.