Authorities Thursday said the preliminary cause of a fire in a Pasadena apartment that left a 4-year-old boy dead, critically injured his mother and 3-year-old brother, and killed a dog, was an electrical problem involving the refrigerator.

Firefighters were dispatched at 2 p.m. Wednesday to 169 E. Washington Blvd., near North Summit Avenue, according to Pasadena’s public information officer, Lisa Derderian.

Crews arrived within three minutes, but a lower-level apartment unit was already well-involved, and flames were spreading to upper units. Fifty-five firefighters extinguished the second-alarm fire at 2:30 p.m., Derderian said.

Keven Arias, whose birthday was on July 24, died at the scene according to the coroner’s office. His younger brother and their 29-year-old mother were taken to a hospital in critical condition, Derderian said. Fox11 reported their names as Jordan and Nancy, respectively.

The preliminary cause of the fire was an electrical problem involving the refrigerator, Derderian said. A dog also died in the fire, Derderian said.

Three smoke alarms were in the residence but were “not sounding” when firefighters arrived on scene, and investigators were working to determine if they had batteries in them, Derderian said.

The American Red Cross assisted about a dozen people displaced from the building. A chaplain program newly implemented by the fire department provided counseling for firefighters at the scene, some of whom have young children of their own, Derderian said.

>> Want to read more stories like this? Get our Free Daily Newsletters Here!