COMPTON (CBSLA) — A teenage boy has died following a fire that filled the room where he and his grandmother with smoke.

Alex Razo, 17, was pronounced dead at 10:29 a.m. Wednesday, according to the Los Angeles County Sheriff’s Department.

Razo and his grandmother, a woman in her 70s known as Lydia, were sleeping when a fire broke out at about 12:45 a.m. Monday in the 16000 block of Essey Avenue, in unincorporated East Compton. The flames did not reach their room, but smoke filled it to the point they had to be carried out by firefighters because they had inhaled so much smoke.

The grandmother remains in critical condition.

Authorities say arson/explosives detail detectives continue to investigate the cause of the fire.