A woman called 911 Monday at around 8 p.m. to say she was on fire, according to Ed Troyer with the Pierce County Sheriff's Office.
Police and firefighters rushed to the Hidden Glen Mobile Home Park in the 7600 block of 159th Street East and found a mobile home on fire.
The woman was taken to Harborview Medical Center, but her condition is not known.
After speaking with the victim, police believe a man poured some sort of flammable liquid on the woman and set her on fire.
The man, who has not been identified, was arrested a short time later, according to Troyer. The man was also burned in the fire.