Ignition problems of the 2009 Mini Cooper

I stopped at a grocery store on the way home from work at approx. 6:30 pm on 11/17/11. I parked the car, turned off the ignition and locked it. When I exited the store approximately 13-15 minutes later, I found the car a smoldering shell surrounded by firefighters. It appeared to have spontaneously gone up in flames. Firefighters could not determine a cause. There was no indication of any problems with the car prior to this incident (car performed "normally" and there were no alarm or flash indicators on the console suggesting a problem. ).