A single campfire likely sparked what is now the largest blaze in Arizona history, and authorities said they've questioned two "persons of interest" as the massive wildfire and two others threaten separate corners of New Mexico.

However, investigators on Wednesday declined to call the two people suspects or speculate on whether they'll face charges or be found liable to pay restitution.

Area residents had mixed feelings about how hard officials should go after those responsible.

"It's done," said Reed Schmidlin, 61, who was evacuated from his Springerville home. "There's not a lot you can do about it."

He said prosecuting those responsible would just add to the fire's cost.

In New Mexico, the tourism secretary said the state had been hoping for a modest rebound in tourism this summer. But with fires burning near three of the state's four borders, she's trying to stay optimistic and reassure people that New Mexico is open for business.

The fire burning in eastern Arizona's Apache-Sitgreaves National Forest continued its cross-border threat to Luna, N.M., as it grew to 478,452 acres of forest, or nearly 750 square miles, fire command team spokesman Alan Barbian said.

Of that, 4,911 acres were in New Mexico and 473,541 in Arizona, making it the largest fire in Arizona history, although nowhere near the most damaging to homes. The fire was about 29 percent contained by late Wednesday afternoon, but authorities were expecting high winds Thursday, Friday and Saturday, with gusts up to 45 mph, fire command spokesman Jim Hyland said.

The blaze forced nearly 10,000 people to evacuate in several small mountain communities and two larger towns on the forest's edge. It has burned 32 homes and four rental cabins.

Arizona's largest fire previously was the 2002 Rodeo-Chediski fire, which burned 732 square miles and destroyed 491 buildings.

About 2,400 people who live in several Arizona resort communities in the forest remained evacuated, said Brannon Eagar, Apache County's chief sheriff's deputy. The order for Nutrioso was lifted and residents began trickling home midmorning Wednesday, and fire officials said evacuation orders for the picturesque hamlets of Alpine and Greer might be lifted in several days.

Greer lost more than 20 homes and a couple dozen outbuildings as flames moved into the valley last week.

Forest supervisor Chris Knopp said a campfire in the Bear Wallow wilderness was the "most likely cause" of the eastern Arizona fire. He confirmed investigators had questioned two people, but he declined to say any more about the investigation.

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Bryan reported from Albuquerque, N.M. Associated Press writer Jeri Clausing in Albuquerque contributed to this report.