When police arrived, the home on Keyman Drive was on fire and all family members, including children, were outside.
Investigators say 18 year-old Christopher Valdez attacked his girlfriend and two others around 7 p.m. Friday.
Deputies believe he used a lighter to set fire to sheets in the mobile home.
Investigators say the two victims who were treated at Betsy Johnson Memorial Hospital have been released.
Valdez is facing first-degree arson charges. His first court appearance is set for Monday.