Lack of Clues Points Authorities Toward Arson : Investigation: Police have no suspects in Laguna fire and find it hard to draw a profile of a typical arsonist. A man was arrested in the Altadena fire.

The contrast is striking. To the north sits a foot-high layer of unbroken sage scrub and dried shrubs that create a wall of yellows and browns along Laguna Canyon Road.

Then, without warning, the scenery breaks. To the south, divided by a winding path that runs past the horizon, is a sea of black--a vast terrain of lifeless dust that covers the ground like darkened Astroturf, crumbling under foot.

This, say Orange County fire officials, is ground zero: the place where an arsonist set a fire that would rage out of control for hours this week, leaving a path of destruction that Fire Chief Larry J. Holms said Thursday would surely total “in the billions.”

Gov. Pete Wilson’s office Thursday announced a $50,000 reward for information leading to the arrest of whomever set the Laguna Beach blaze.

But for now, investigators say they have few clues about who might have set it. Bottles, cups, broken class and other debris lie scattered around the flash point--some 100 feet west of the canyon road, about a mile south of the San Diego Freeway. But officials say little else remains in the way of pointers.

In fact, officials say it was the absence of any noticeable evidence at the scene--a downed power line, for instance, or anything else that may have set off the blaze accidentally--that led them to conclude that the blaze was set.

Two unidentified witnesses spotted the Laguna Canyon blaze “at a very small stage,” Holms said, shortly after it began around 11:45 a.m. Wednesday in the brush, allowing investigators to determine “exactly where it started.”

Holms said the witnesses attempted to put out the blaze--he did not know how--but it raced unimpeded toward the shore, driven by strong Santa Ana winds. It ultimately swept through nearly 12,000 acres, damaging or destroying more than 300 homes.

Unlike this week’s fires in the Anaheim Hills/Villa Park area--in which a person in a black Pontiac Fiero was spotted speeding from the scene--fire officials said no one has reported seeing possible suspects in the canyon at the time the fire started.

“You talk about frustrating,” said Capt. Dan Young, a spokesman for the Orange County Fire Department. “They just destroyed the community.”

The fire may have been the work of a “copycat” arsonist who was imitating the havoc caused earlier in Ventura and Los Angeles counties, officials speculated.

“Historically, that’s often the case. I don’t know about this one,” Young said.

But Orange County Supervisor Gaddi H. Vasquez said he knows one thing for certain after touring some of the debris around Laguna Beach on Thursday morning with Gov. Pete Wilson and local authorities: “The person who would do something like this is sick and, frankly, pathetic. . . . Obviously, in this type of climate, the danger was enormous.”

As they surveyed the damage in Laguna Beach and throughout other areas of Southern California, arson experts said it was criminals, just as much as high winds and dry brush, who spread this week’s fires with such terrifying speed. Arsonists often are stimulated by the clamor surrounding fires, and experts say the police and news reports of the Altadena blaze may have encouraged arsonists to leap into the act.

“A lot of these arsonists have scanners. They’re listening to the calls, and that excites them,” said Doug Allen, president of the California Conference of Arson Investigators. “That’s all part of the thrill.”

Of at least four Southland fires caused by people this week, only one suspect was in custody Thursday. Arrested on suspicion of recklessly setting a fire in connection with the blaze in Altadena, which destroyed 100 homes, was Andres Z. Huang, 35.

According to authorities, Huang had taken refuge from gusting winds Tuesday night in a small gully a mile north of the Eaton Canyon Observatory. He awoke shortly before dawn, shivering with cold. Authorities said that Huang, a native of China who came to the United States about two months ago from South America, lit the fire to keep warm, but that it got away from him, igniting the canyon’s thick brush.

Frightened, Huang got up to run, but he tumbled down a hillside, hurting himself, authorities said. “It was an illegal fire, but not arson. He was not out to do this,” said Los Angeles County fire department spokesman Clark Pearson.

Huang is in the County-USC Medical Center jail ward.

The search for those responsible for the other fires has only just begun. Local authorities are handling those investigations, but the Bureau of Alcohol, Tobacco and Firearms has offered its assistance.

The very nature of the crime makes clues in arson cases extremely hard to come by. Every fire destroys much of the evidence, and what’s left is often ruined by fire crews, whose priority always is putting out the blaze, not preserving the crime scene.

Still, sometimes the cause of a fire is obvious. A San Bernardino County blaze that erupted Wednesday morning has been blamed on power lines, while a San Diego County fire was attributed to children playing with matches.

However, more often investigators’ inquiries are laborious and only settle on arson after every other possible cause--from lightning to spontaneous combustion--is ruled out.

“It’s probably the hardest crime to solve,” said Allen, who investigated fires for 30 years as a California Department of Forestry official. “It is like putting together a mosaic puzzle without all the pieces.”

Arson cases are one of the least often solved--and most costly--of all crimes. According to FBI statistics, suspects were arrested in just 17.3% of all suspected arsons last year, compared with arrests in half of all rapes and 65% of all suspected murders.

Sometimes, however, authorities get lucky. When fire investigators picked through the rubble of one 1987 Bakersfield blaze, they found the remains of an incendiary device, a cigarette butt and matches wrapped in yellow legal paper. What’s more, the paper had a smudged fingerprint.

Government experts concluded that the print belonged to John Orr, a nationally acclaimed arson investigator with the Glendale Fire Department. Then they discovered that Orr had written a 418-page manuscript, titled “Points of Origin,” about a serial arsonist.

Prosecutors eventually succeeded in winning the right to use as evidence the manuscript and letters that Orr had written to literary agents. Although he proclaimed his innocence, Orr was convicted. He is now serving a federal prison sentence.

It is surprisingly common for arsonists to record their crimes. Many arsonists keep diaries or logs, experts said, and those documents can provide damning evidence at trial.

Although experts cautioned that it is difficult to draw a profile of a “typical” arsonist, some said that they do share traits. Many are loners who work by themselves, planning their crimes in great detail. They often admire authority figures, sometimes going so far as to buy police or fire uniforms. They show little, if any, compassion for the property or people they destroy, using the fire as a way of venting anger. They like to watch the fires they set. And, if not caught, they tend to strike again and again.

Those traits, however, can be misleading.

“There are so many stereotypes,” said Dr. Lawrence Sporty, a senior lecturer in psychiatry at UC Irvine who has worked with arsonists. “But the truth is, they come from all walks of life. You see fires started by everyone from people who work in fire departments to people who suffer from mental illness. . . . They get some kind of pleasure from doing this.”