A fire deemed 'suspicious' by Sparta police has been ruled an arson, according to a report on NJ.com.

A Fox Trail Road home was gutted Thursday night by the quick-moving fire, and resident Lindsay Kiensicki, 26, suffered burns to her head, face and arms, Sgt. John-Paul Beebe had said. Homeowners Robert and Lois Kiensicki were not home at the time of the blaze, Beebe said.

Investigators initially deemed the fire suspicious, and the Sussex County Prosecutor's Office is investigating it as a case of arson, NJ.com reported.

"There's no cause for public alarm," First Assistant Prosecutor Greg Mueller said.

Kiensicki remains in critical condition at St. Barnabas Medical Center.