A large fire the destroyed an apartment tower under construction in downtown Los Angeles and shut down two major freeways during Monday morning rush hour may have been arson, authorities say.

It took 250 firefighters to subdue the blaze at 909 West Temple Street, which also damaged two nearby buildings, with one suffering radiant heat damage on three floors while the other received fire damage on three floors and water damage on the other 14, according to the fire department as quoted by a Los Angeles Times report.

Fires of this size are typically treated as criminal fires, and officials believe that this one may have been intentionally set, according to the Times.

Fire official Capt. Jaime Moore was quoted in the report as saying that it was “very rare” for and entire building to become completely engulfed in flames so quickly, indicated some foul play. Authorities brought in dogs to sniff for accelerants.

The fire caused damage to the headquarters for the Los Angeles Department of Water and Power, with heat cracking 160 large windows. The department will have to move its workers and board windows up while keeping service open for customers, warning that those needing assistance would have to wait a while before anyone could answer the phone.

The building, which was the size of a city block, had 1.3 million square feet of floor space, two-thirds of which was engulfed in flames. Most of the fire was extinguished in 90 minutes, and firefighters dealt with hot spots throughout the morning, according to the fire chief.

No one was injured in the fire. The Bureau of Alcohol, Tobacco, Firearms, and Explosives joined authorities on the scene to investigate the suspicious situation.

The building, DaVinci Apartments, was located just 100 yards from a fire station. As soon as firefighters emerged, the building was completely engulfed in flames, with flames climbing 40 feet above the seven-story structure.

The two buildings that were damaged housed the Department of Parks and Recreation and L.A. County Health Services. Employees there received emails telling them to work elsewhere, as both buildings were not to be occupied “until further notice,” according to the report.

The building is located right at the interchange between the 101 and 110 freeways. Parts of the apartment building’s scaffolding fell over a freeway wall near the interchange, snarling traffic.