The Los Angeles Fire Department responded to the 1500 block of W. Cambria St. shortly after 8 p.m. where heavy fire was reported in the attic.
AIR7 HD was above the scene, capturing flames fully consuming the attic while also spreading to the top floor. Firefighters prevented the fire from spreading downward into any first floor units.
LAFD said it took 74 firefighters about 45 minutes to extinguish the flames.
Thirty-seven people were displaced, though no injuries were reported.
The cause of the fire remains under investigation, but arson investigators detained a man at the scene for questioning.
Silver Lake residents worry about arsonist after 20 tree fires in one month
Thursday's incident comes as police continue to search for an arsonist targeting several neighborhoods.
Over the past month or so, authorities say there have been nearly 30 tree fires in and around Mt. Washington, Glassell Park and Silver Lake.
It's unclear if the person detained Thursday is related to those other incidents.