An arson investigation has been initiated over a four-alarm fire that broke out at a Nob Hill apartment building on Saturday evening, bringing over 120 firefighters to the scene and injuring three residents.At least three people were injured and a dog was reported missing after a four-alarm fire bro ke out at a multi-unit apartment building at Washington and Larkin Streets in Nob Hill on Saturday evening at around 5:52 p.m., according to CBS News. Over 120 firefighters were called to fight the blaze, which was extinguished by 8:30 p.m. Crews were expected to remain on the scene for several hours.The San Francisco Fire Department said on X that the fire spread throughout all three floors of the building, extending to the roof, and adjacent buildings were also damaged. A person in a wheelchair was pulled from the building, and two people required assistance down the stairs. 4th Alarm working fire - Washington / Larkin Street - 1705 hours on 04/05/2025A large working fire has been declared on Washington Street, 4th alarm. The fire has extended throughout the building. All three floors have been burned. The buildings next to the fire building have… pic.twitter.com/em9BFPLNSa— SAN FRANCISCO FIRE DEPARTMENT MEDIA (@SFFDPIO) April 6, 2025 One resident was reportedly taken to the hospital, and others were treated at the scene. It wasn’t clear how many people were displaced or what caused the fire. According to KRON4, an arson investigation has been initiated.Image via Citizen app ...read more read less