If such "accident" or anything happens to the database no one would believe it. Backups are common sense especially for websites handling money.
If this happens it would be clear why. And i fear the anger of people could be enough for him to fear for his life. I mean even now there is so much anger. How will it be when its clear he killed the database? I will not imagine.
It doesn't matter whether people believe it. Take a look at the Bitcoinica clusterfuck. All the anger in the world still hasn't gotten people their funds back and the Intersango guys aren't exactly in hiding.