[Western Phil]

The street level Google earth pictures of this property may give more detail: http://maps.google.com/maps?q=800+a+street+se+washington+dc&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&hq=&hnear=800+A+St+SE,+Washington+D.C.,+DC+20003&gl=us&ei=ipFUTcGiEMXZgQfrhLXiCA&sa=X&oi=geocode_result&ct=title&resnum=1&ved=0CBMQ8gEwAA

The one from above shows their second car parked diagonally so that one would have to leave the garage at an angle..

[TigersEye]

The way that car is situated makes it look like a real challenge to back out and around from the garage. I can imagine an oversteer that caused the front of the car to hit a work bench on the house-side wall. That could have upset some flammable materials onto some kind of ignition source. That would then be the car's only role in starting the fire.

But that leaves the question of why the door was closed and raises the question of why this anti-freeze-headlight theory was put forward by the authorities. Fire investigators for fire departments are usually pretty good and it shouldn't be that hard to find the ignition point and the initial accelerant.

One possibility I overlooked for a stairway and entry into the garage would be from the basement level up to the garage. But the entry door on that stoop would seem to rule that out. The headroom for that stairway would impinge on what we've been calling a mudroom behind the door on that stoop.