Officials said Sunday they discovered that the cellar of a Crown Heights building that caught fire was illegally converted into apartments.

Members of the FDNY handed out smoke alarms and educated the community about fire safety just across the street from the site of Friday's deadly fire in Bedford Avenue.

"We come out, we give free smoke detectors and talk to people, make sure they have a plan in case they need to get out. Just having a working smoke alarm in your house cuts your chance to die by 50%," said FDNY Lt. Jim Colby.

A partial vacate order was issued for the building for four units that were damaged on the fourth floor and additional illegal conversion units that FDNY says were discovered in the building's cellar during an inspection Friday.

According to the FDNY, the units had bedrooms, communal spaces, kitchens, lacked proper exits, windows, and ventilation.

The Red Cross tended to all the residents who were displaced.

Fire officials told News 12 those illegal units are especially dangerous during fires.

"The fires spreads quicker and a lot hotter, so you need to get out quicker. Now something happens, you're trapped, and people often don't have smoke detectors in those rooms especially," Colby said.

Two citations were given to the landlord for those illegal conversion units, according to the FDNY.

The fire marshal's office was still investigating the cause of the deadly blaze as of Sunday evening.