Authorities are investigating to determine the cause of an East New York fire that left dozens displaced on New Year’s Eve.

The FDNY was back at the building on Schenck Avenue Tuesday morning. Boulevard Together, the building's property management company, was also there assessing the damage.

The FDNY says construction material in the courtyard of the Boulevard Houses caught fire Sunday night and evolved into a massive blaze spreading to 13 apartments.

Residents tell News 12 that they heard fireworks going off near the courtyard before the fire.

Once the flames were knocked out, they say they saw an empty cannister being looked at by nearby emergency crews.

Since Sunday, tenants and those who live nearby have stopped at the building in awe of the destruction.

"The amount of damage and the amount of displaced residents here, just looking at the amount of apartments, this is a lot. This is a lot to happen right before New Years and after Christmas," said a man who lives down the block.

Residents say they are waiting to learn whether those fireworks played a role in the blaze. The FDNY has yet to release an official cause.