3:30 AM: We’re checking out a fire call in the 5900 block of 39th SW (map) – crews originally were dispatched to an address on Fauntleroy Way, but scanner traffic has changed the location. Doesn’t sound big but they are calling for the investigator (Marshal 5). More when we get there.

3:42 AM UPDATE: At the scene, SFD tells us this was a small fire in some building materials behind what appears to be a construction/remodeling project. A neighbor who happened to be awake saw it and called it in to 911, and it was extinguished quickly. No injuries and no damage beyond the “building materials,” we’re told, but the investigator will have to figure out how it started. (Thanks to everybody who texted/e-mailed/tweeted about this!)

9:31 AM UPDATE: Just checked with Lt. Sue Stangl at SFD. Investigators couldn’t figure out exactly what started the fire, so the cause will remain officially “undetermined” – but she added that they found no evidence it was “suspicious.”