Christopher Zehr surveys the destruction at his father's incinerated house on Mesquite Tree Lane in Sierra Vista. He had access to the property on Thursday. The home was among dozens destroyed when the Monument Fire roared down from the Huachuca Mountains.

GREG BRYAN / ARIZONA DAILY STAR

SIERRA VISTA - The Border Patrol said one of its agents spotted the early stages of what would become the Monument Fire as the blaze near the U.S.-Mexico border was beginning to grow.

Border Patrol spokesman Steve Adkinson said the agent who reported the fire wanted to extinguish it but realized it was too big to fight.

The agency's statement comes after Cochise County Sheriff Larry Dever said he believed illegal immigrants started the 47-square-mile fire, which has been burning south of Sierra Vista since June 12.

"There is no other logical assessment available - not fireworks, not campfires, not someone passing by in a vehicle. It was somebody on foot in a high-intensity foot-traffic area," Dever said last week, adding that the area where the fire started was remote and closed to visitors.

Dever had said a border agent had been pursuing a group of illegal immigrants nearby when the fire broke out. Adkinson said the agent wasn't chasing migrants but was instead looking for footprints and other signs of border crossers.

Investigators declined to say whether the human-caused fire was started by illegal immigrants.

Meanwhile, crews have the fire 85 percent contained after the blaze burned 30,500 acres. Crews spent Monday improving fire lines and mopping up.

The U.S. Forest Service says infrared detection shows a few isolated hot spots in Carr and Oversight canyons within the fire perimeter. Isolated columns of smoke are expected to rise until monsoon rains put out the last of the flames.

On StarNet: For the latest news, photos, interactive maps and videos on Arizona wildfires go to azstarnet.com/wildfire

record heat

Tucson tied a record high for the date Monday, and we've gone 79 days without rain.

That ties the streak for the sixth-longest stretch.

See story, Page A2