The Roslyn Fire Department responded alongside 36 other Nassau County fire departments to an office building fire in Flower Hill on Saturday evening.

The Nassau County Police Department said in a Feb. 6 report that the cause of the fire at 1025 Northern Blvd. was undetermined and under investigation.

Three firefighters sustained minor injuries during the response. They were treated at local hospitals and released.

Newsday reported the building’s roof, second and third floors had collapsed due to the fire. The ground floor and the basement of the building also had extensive water buildup.

A Roslyn Fire Department official told Newsday that the fire was well-advanced by the time of their response at 5:45 p.m., leading them to believe it had been burning for a while before crews arrived on the scene.

Responders at the scene included the Fire Marshal Hazmat Office, Fire Marshal Investigators Office, the Office of Emergency Management, Fire Chief Jordan Williams, Arson Bomb Squad detectives and 6th Squad detectives.