From the CNN story at the link, at 5:34 pm

Person believed to be renegade ex-LAPD officer Christopher Dorner killed deputy, wounded another in shootout at southern California cabin Tuesday, authorities say
Hours later, sources say, police assaulted cabin, which caught fire; we're awaiting details

??????

The cabin "caught fire"?

I have no proof because the media are going along with the news blackout that the police have demanded, but it seems more plausible that the police are afraid to go in, or don't want to negotiate a surrender, and are burning down the building.

If there's no exit, Dorner will probably choke to death on smoke, then his corpse will be burned in the fire.

They might say that Dorner set the fire, but does that really make sense?