LONGVIEW (AP) — Fire officials say a late night fire ripped through an RV where a family was temporarily living, killing a 3½-year-old boy and injuring five others.

Longview Fire battalion chief Troy Buzalsky said the boy’s mother, father and 2-year-old sister escaped through a window but the boy was trapped. The father was critically burned as he tried unsuccessfully to break down the trailer door to rescue his son.

The father was taken to Legacy Oregon Burn Center in Portland, in critical condition. The mother and sister were also injured, along with the boy’s grandmother and neighbor, who were not living in the RV.

Bulzalsky says witnesses told investigators that the wife woke just before midnight Thursday to her husband’s screams. The 20-foot trailer was filled with thick, hot, black smoke. The blaze blocked the front door.