(Photo sent by David)

1:22 AM: A Seattle Fire “full response” is headed to the 4700 block of 42nd SW. SFD says the initial report is “light smoke in an apartment building. More to come.

1:25 AM: The address has been updated to 4100 SW Edmunds, the Elan 41 apartments at Jefferson Square. Firefighters on scene are reporting “heavy black smoke” from one side of the building.

1:28 AM: Per scanner – we’re still on the way – flames visible from the second floor.

1:33 AM: Added photo sent by David. SFD crews report fire “knocked down.” SFD reports its first search of the “fire floor and floor above” are “all clear.”

1:36 AM: SFD now reports the fire “under control.” (added) Also from radio communication – one firefighter is reported to have minor injuries.

1:41 AM: Our crew just arrived – adding photo of one of two ladder trucks on scene. This is in the section of the apartments that’s over the east side of Jefferson Square businesses.

1:56 AM: Fire now reported “tapped.” No other injuries reported so far. Our crew says the injured firefighter is a lieutenant who’s been treated by medics and will be OK. The firefighting itself is ramping down but now crews are checking into possible water problems elsewhere in the complex.

2:10 AM: SFD tells us on scene that the residents of the apartment where the fire started were not home at the time. They’re checking adjacent apartments for extension/damage. Also, the injured lieutenant will be checked out at Harborview. A pipe break is reported to be contributing to water problems elsewhere at Jefferson Square, including the parking garage and animal hospital.

2:33 AM: They’re continuing to mop up that water. Some SFD units, meantime, have been dismissed.

3:02 AM: No word yet on the fire’s cause.

10:50 AM: Via Twitter, SFD says the fire was “intentionally set” and that police are investigating. Damage is estimated at $120,000.

1:50 PM: SPD just announced that a resident of the apartment was arrested for investigation of arson after saying he started the fire.