The homeowner and a neighbor rescued four of the felines as flames destroyed the home in Wayne Monday.
Police Capt. James Clark told the Record newspaper investigators believe a faulty light fixture may have started the fire.
It took firefighters from three fire companies two hours to get the upper hand on the flames.
Township fire inspector Scott Kooreman told The Record newspaper Tuesday that more cats are believed dead and trapped in the house but that a floor collapse had made the building unsafe for firefighters to enter.
Information from: The Record of Bergen County, http://www.northjersey.com