HUMBOLDT, Tenn.  — A house fire in West Tennessee has killed a 7-year-old boy and injured his mother.

Humboldt Fire Chief Chester Owens the woman and her two daughters and son were inside when the fire started around 2 a.m. Monday.

The mother and daughters were taken to a hospital. Owens said the mother was injured trying to get back inside the house to save her son.

Humboldt Police Chief Rob Ellis said the boy died of smoke inhalation.

The cause of the fire was under investigation. The cause is undetermined, Owens said, but the fire is believed to have started in the front of the home. State Bomb and Arson and Humboldt police are assisting in the investigation.

Owens said the home was fully engulfed by the time fire department crews arrived, fire crews didn’t find any working smoke detectors in the home.