The body of an unidentified man was discovered in a motor home that was found burning early yesterday morning, Arlington police and fire officials reported yesterday.

A police spokesman said there were "no obvious signs of any criminal activity" leading to the death. Fire officials said the cause of the blaze is still under investigation. "At this point anything is possible," said Deputy Fire Marshal Henry Dayton.

Officials said several people called the emergency 911 line to report the fire at 4:42 a.m.

When firefighters and police arrived, they found a 1972 Dodge motor home parked about 100 feet back from the street on a lot next to 3817 S. Ninth St. "It was engulfed in quite a lot of flames," Dayton said.

Dayton said the blaze took 10 to 15 minutes to extinguish. "The body was found during the overhaul portion of the fire, when they start tearing things apart" to see if any material is still burning, he said. The badly burned body was found lying face down near the front of the motor home, officials said.

The fire also damaged an MG convertible parked nearby in the lot. Fire officials estimated total damages at $20,000.

Dayton said officials were still trying to determine the owner of the motor home, which did not have license tags.

Kenneth R. Kozel, one of the neighbors who reported the fire, said he was lying half-awake when he heard a loud sound. "It was like a boom-type thing. It didn't bother me at first. Then two minutes later, I heard it again; it sounded like a popping noise."

When he looked out his bedroom window, Kozol said, the house next door was "almost white in the glare from the fire. Then I saw the reflection of orange in the windows."

Kozol said he ran to the other side of his house and checked a window that faces 3817 S. Ninth St. "That's when I saw the [motor home]. At that point, anyone who was in there was gone; it was just like an inferno."

Police said an autopsy is scheduled for tomorrow.