BROOKLYN - Investigators are trying to figure out what sparked a blaze that officials have deemed "suspicious" inside a vacant Bushwick home. 

Firefighters were called to the three-alarm fire at around 1 a.m. Tuesday. Viewer video shows flames bursting from the building at Putnam and Bushwick avenues.  

Authorities say the fire spread through all three floors, but it was entirely empty and all utilities were turned off. 

Several residents were evacuated from the building next door, but have since been allowed back inside and no injuries were reported. Neighbors say that although the home has been vacant, they have seen people going in and out.