An off-duty Border Patrol agent is being investigated for possibly starting a large wildfire in southern Arizona while target shooting last weekend, authorities said Thursday.
Border Patrol officials said in statement that they were aware the investigation about how the fire began Sunday "involves an off-duty Tucson Sector Border Patrol agent" that they did not identify.
"The agent was involved in recreational shooting and immediately reported the fire after it begun," officials with the Tucson Sector added.
They referred all questions about the investigation to state fire officials, who were holding an informational meeting Thursday night in Cochise County and didn't immediately return calls seeking comment.
A spokesperson for the Coronado National Forest declined comment on the ongoing investigation.
U.S. Forest Service law-enforcement personnel are investigating the cause of the fire and officials previously said it was human-caused because there was no lightning nearby when it started Sunday about 10 miles (16 kilometers) southeast of Green Valley.
High winds Thursday afternoon forced officials to ground aircraft as crews worked to contain the wildfire that has burned 63 square miles (163 sq. kilometers) of grass, brush and trees on a 45-mile-long path.
Firefighters took advantage of reduced winds Wednesday to build containment lines around 30 percent of the fire's perimeter, up from 7 percent a day earlier, but forecasters issued red flag warnings of stronger winds into Friday with possible gusts of up to 35 mph.
Combined with low humidity, the stronger winds make for "prime fire conditions," said Manny Cordova, a spokesman for incident management team overseeing the firefighting effort.
"Any fires that develop or are ongoing will likely spread rapidly," the National Weather Service said.
Arizona Gov. Doug Ducey said Thursday that he was requesting the use of an unmanned aerial drone operated by the state's National Guard to help first responders in the firefight.
The move is seen as a potential cost-saving plan because the drone would help the incident management team allocate resources more efficiently.
The high-risk weather also has prompted fire officials to warn the public to be vigilant against accidentally starting fires from sparks from machinery or from chains dragged by vehicles.
Pre-evacuation notices are in effect for hundreds of homes in rural areas of Cochise County near Interstate 10.
The fire so far has coursed through sparsely populated areas, forcing limited evacuations and closing a state highway but causing no reported structural damage.
Cordova said 80 to 100 dwellings have been evacuated during the fire, but some people have been allowed to return to their homes.
Those include 11 nuns who were provided overnight shelter at a bed-and-breakfast after being ordered to leave their abbey before the fire changed direction.
Evacuation centers have been established in the area, but most evacuees have stayed with family and friends.