A wildfire (search) that menaced parts of the city was started by a firecracker tossed onto a pile of cotton from a cottonwood tree, one of the teens accused in the case told investigators.

Ricky Navarette, 16; Fernando Anaya, 13; and Steven Sedillo, 13, all of Albuquerque (search), were being held Friday at the Bernalillo County Juvenile Detention Center (search). They are accused of setting the first of two fires that burned along the Rio Grande bosque in Albuquerque this week.

Sedillo said Navarette also used a lighter to ignite debris.

"What did we do?" one of the boys allegedly said when he got home and saw the fire on TV, according to the arrest warrant affidavit obtained by the Albuquerque Journal.

Charges included arson and criminal damage to property over $1,000, police spokesman Jeff Arbogast said. Sedillo also was charged with tampering with evidence.

Navarette told police Sedillo lit the firecracker Tuesday and threw it on the cotton pile and the fire quickly spread, the affidavit states.

After receiving tips, police issued search warrants for the boys' homes late Wednesday. Arbogast declined to say what officers found.

Tuesday's fire burned 352 acres and forced the evacuation of hundreds of people as it raced north through the heavily wooded area along the river. The fire was 75 percent contained Friday.

A second fire, sparked Wednesday night about a mile north of the first, burned 165 acres and forced about 200 people from their homes. It was 50 percent contained Friday.

No arrests had been made in the second fire, authorities said.

Some 400 firefighters were working Friday to reinforce fire lines around the two blazes so they can work their way into the interior. Water-dropping helicopters were helping intermittently.

In California, firefighters struggled Friday to contain a wind-driven wildfire burning through a rugged high desert recreation area about 150 miles north of Los Angeles.

The blaze, which destroyed one home, a mobile home, a barn, a shed and a trailer on Thursday, suddenly expanded as winds picked up about Friday afternoon. Firefighters quickly went from about 80 percent containment of a 200-acre fire to 25 percent containment on a 400-acre blaze.

Most residents had complied with a voluntary evacuation of about 200 homes, officials said.

And investigators in Arizona say they have no suspects in a human-caused wildfire that devastated a mountaintop vacation community. While the exact cause was not determined, the origin of the fire, which burned about 324 buildings on Mount Lemmon near Tuscon, was narrowed to a small area near a trail southwest of Summerhaven.