First we thought it was just a motorcycle accident. No big deal. Then it turns out there was a young woman riding on the back and a possible affair with the woman and complications from that. Now it turns out that a couple drove Petrino and the young woman to a rendevous point away from the accident and there is also an Arkansas State Trooper involved, who was scheduled to do a fugitive pickup but instead investigated the accident.
At this point, there are more questions than answers, but the coverup seems far more elaborate than anybody thought. Here are a few links with updates to the story:
Update: Here's another story that includes additional details: