Mendocino County authorities are working to identify charred human remains recovered from a rural home that burned down Wednesday afternoon.

Authorities believe the victim might be a resident of the Radical Ridge Road home outside Redwood Valley, but the remains were burned beyond recognition, making immediate identification impossible, Mendocino County Sheriff's Lt. Greg Van Patten said.

Reported around 3:45 p.m. Wednesday, it was the second fatal fire in Mendocino County since Saturday, when an 87-year-old man and his developmentally disabled son died in a fire in Potter Valley.

Investigators have not determined the cause of the Saturday morning fire that took the lives of Earle McDaniel and his son, Wesley McDaniel, 55.

Authorities say it is still being labeled suspicious, though "there's nothing that's obvious and glaring at this point" to suggest anything but an accidental cause, Van Patten said.

Wednesday's incident "was very similar to the kind of devastation that we experienced in Potter Valley," he said. "The structure was completely burned to the ground."

The blaze broke out west of Redwood Valley in remote woods about six miles from Highway 101, Cal Fire Capt. Tod Patten said.

The fire spread so quickly that the house was engulfed in flames when fire crews arrived, he said. Flames spread to about three acres of vegetation and burned up into the trees.

"The mop-up is going to take several days," Redwood Valley Fire Chief Tom Hession said.

It was more than two hours before a fire prevention officer located the human remains, authorities said. An autopsy was scheduled for today, Van Patten said.

Fire officials also were still investigating the blaze to determine a cause, "but, again, it's going to be very difficult to get cause and origin based on the damage to the structure," Van Patten said.

There were no obvious signs of foul play, but authorities are asking anyone who may know anything about the fire to call 234-2100.

You can reach Staff Writer Mary Callahan at 521-5249 or mary.callahan@pressdemocrat.com.