Kevin's story is backed up by MtGox's own feed; and that showed that he could not have made the order before the crash. In fact, 6 people got in before him when the large order finally finished executing - which took 35ish minutes.
This.
Which of course begs the question of why magicaltux would try to pin this whole thing on someone he knows most likely had nothing to do with the hack. The obvious answer here is that he needed a scapegoat and he needed one fast. The sooner people start blaming Kevin the less heat magicaltux and thus mt gox will have to take. He must know that legally he can't put over any responsibility for this on kevin so I assume he's doing this because he hopes that he can get mt gox back to its former glory after this is over with. I for one am not going to make a single trade there.
The current evidence stacked up again Kevin is that he was logged in when the crash happened and that he's apparently good with computer security. While this is apparently enough to convince some of the lesser minds on these boards I somehow doubt it's something that would hold up in court.