A lightning strike was determined to be the cause of a house fire Friday evening in Ruskin, according to officials with Hillsborough Fire Rescue. Authorities said the fire broke out at a home on Dovesong Trace in Ruskin around 5:50 p.m. Fire crews initially reported that no smoke or flames were visible from the front of the home. However, it took firefighters less than one minute to determine the fire was in the attic, authorities said. Firefighters managed to extinguish the flames in the attic in approximately five minutes. There were no reported injuries. An investigation determined the cause of the fire was a lightning strike.