The San Jose fire Department reports the fire broke out inside one unit of an apartment house in the 500 block of S. Ninth St., around 5 a.m. Saturday and quickly went to three alarms.
Neighbors say a family of four lived in the unit.
A teenage girl and a man in his early 20's died at the scene. Two other people, identified by neighbors as the victim's parents were taken to the hospital with critical injuries. One of those victims later succumbed to their injuries.
"I am so sad right now, this is horrible I see the kids going to school all the time, the family was very nice and kind," said neighbor Jomar Lacsina.
A cause of the fire has not been determined but firefighters believe it started in the kitchen. Firefighters are investigating if smoke detectors inside the apartment were working.
"Whether they were or not, their task did not get accomplished, for whatever reason these poor people were not awoken in time to get out safely," said San Jose Fire Department Captain Mike Van Elgort.