New York (CNN) The Trump Tower apartment where a deadly fire started Saturday had no working smoke alarm, a New York City Fire Department source familiar with the investigation said -- which means there was no alarm sounding in the unit when firefighters arrived.

The fire on the 50th floor of the New York City highrise left one man dead and six firefighters injured, the FDNY said. The victim was identified as Todd Brassner, 67.

The FDNY was notified of the fire by a building-wide alarm system in Trump Tower, the source said. This system alerted the fire department to the location of the fire, including the floor of the blaze. Such alarm systems are common, and they are not audible in the entire building to prevent people from evacuating all at once and clogging staircases for firefighters.

The fire was contained to the 50th floor of the apartment building, which is located on Fifth Avenue in Manhattan. The President resides in the penthouse when he's in New York City. No members of the Trump family were in the tower during the fire, Fire Commissioner Daniel Nigro said.

The upper-level residential floors of the 58-story building are not equipped with fire sprinklers, Nigro said.

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