An unnamed individual was arrested last night as a suspect in the starting of the Rodeo fire in Arizona, Mr Pete Pierce, an information officer with the fires task force, announced in Show Low.
The suspect is due to appear before a federal magistrate today in Flagstaff, Mr Pierce said. A federal prosecutor was also due to arrive today, Mr Pierce said.
The announcement came as residents returned to Show Low, most of them to find their homes had been saved by firefighters.
Fire crews shifted away from Show Low toiled outside the tiny enclave of Forest Lakes, about 35 miles to the west, to stop the blaze that is using the sides of canyons as chimneys to catapult embers over nearby State Route 260.
If the massive wildfire, which has overrun 447,000 acres, jumps the highway, it could roar unabated through fuel-rich Ponderosa pine for at least another 30 miles, fire officials said.