However, I don't understand why the difference in gun time and chip time is a big deal. If it was a big race, and you started mid or back of the pack, 4-5 minutes difference is common. Of course, if you are running a sub 3 hr marathon, why would you want to start 4-5 minutes back? Anyway, am I missing something?
The mere fact that there is a large difference doesn't, by itself, speak to whether
he cheated -- starting at the back is a legitimate starting 'strategy' (though a silly one if you are going to run fast). It is, however, apparently relevant. One current working theory, supported by photographic evidence, is that he hangs out in 'civilian' clothes and surreptitiously saunters across the timing mats. That would be easy to do at the back. And even in races where he apparently does actually run at the beginning (cutting the course elsewhere), he wouldn't want to be at the front because the front-runners would notice him magically appearing and disappearing throughout the race.