Killed were Dr. Elvira Romagosa, 64; her daughter, Ren Aubrey Romagosa-Morano, 27, a physical therapist; her granddaughter Gabrielle Athen, four; and their housemaid, Maming Asaldo, 68.
Arson probers said the one-hour fire began at the first floor of the Romagosa residence, which was made of wood, at about 1 a.m.
Superintendent Romeo Mapalo, Camarines Sur police director, told The STAR that his men and the arson probers were still determining the exact cause of the blaze.
The victims neighbors, however, suspect that faulty connections of Christmas lights or the candles which the Romagosas usually kept lighted overnight at the altar triggered the fire.
The police said Morano and Asaldo were still rushed to the Bicol Medical Center in Naga City but both died later that day.
Before she lost her breath, Asaldo said she tried to come to the rescue of the Romagosas who were trapped in a room but failed.