Charges Expected Today in Universal Studios Fire : Arson: Sifting of ashes continues for evidence to support the suspect’s confession. His mother says he is antisocial and can’t handle stress.

Authorities plan to file arson-related charges today against a security guard in the multimillion-dollar Universal Studios fire after making significant progress in an intense search for evidence corroborating the suspect’s confession, investigators said.

Although the suspect, Michael J. Huston, 40, of Tujunga, has admitted his involvement in the blaze to investigators and family members, Los Angeles County sheriff’s arson investigators said they must find physical evidence in the charred and water-soaked rubble linking him to the fire that destroyed or damaged 20% of the sets on the 420-acre back lot.

Sheriff’s officials estimated damage at $25 million.

Investigators face a time limit because under state law Huston, who was arrested Wednesday morning, must be charged or released today. Lt. Ken Chausse, head of the sheriff’s arson unit, said investigators cannot seek charges from the district attorney’s office based on Huston’s statements alone.

“We have strong admissions from him, but you can have anybody come up and tell you they did something,” Chausse said. “You have to corroborate it, or it doesn’t mean anything.”

“We are reasonably sure we’ll be able to present a pretty good case” when charges are filed today, Sheriff’s Sgt. Dale Underwood said. He declined to comment on what had been found and said that the search would continue.

Floodlights were set up at the scene as dusk fell Thursday. A team of at least 10 investigators from the sheriff’s arson unit and the federal Bureau of Alcohol, Tobacco and Firearms had divided the debris in grids and were painstakingly sifting through it, sometimes on hands and knees, Underwood said.

Investigators declined to comment on how Huston is believed to have set the fire, or on a motive.

A source close to the investigation said arson experts are looking into the possibility that Huston set the blaze in order to report it and, thus, look like an exemplary employee. Huston is believed to be one of several people to report the fire, the source said.

The suspect’s family has described Huston as mentally disabled by exposure to chemicals in the Army in Vietnam and by an electrical shock in a back-yard accident three years ago.

His mother, Debra Dragusica, after visiting her son at County Jail Thursday afternoon, said he told her he set the fire with a cigarette lighter.

“He says his mind switched off,” Dragusica said. “He says it wasn’t him when he did it. . . . When he realized what he did, he ran to get help. In the meantime the winds spread it all over.

“He is so sorry. He broke down and cried three times.”

Dragusica said her son, a chain smoker, is antisocial and prone to confusion when under stress.

“He can’t handle a lot of stress,” she said. “He has always been very slow mentally and he can’t function on his own. I have to help him with everything.”

Dragusica said her son had not held a permanent job for nearly 10 years.

She said repeated efforts to get him assistance through the Veterans Administration have been unsuccessful. “He needed help for a long time and nobody would listen,” she said. “Maybe now he will get the help he needs.”

VA officials familiar with the case could not be reached.

Huston was hired last month by Burns International Security Services, which contracts to provide guards at Universal. According to state records, Huston was issued a temporary security guard’s license Oct. 10, allowing him to work after taking a two-hour instructional class and open-book test provided by Burns. His application for a permanent state license was still being processed by the state Department of Justice.

Applicants are not asked if they have mental problems and the state checks for criminal background only, said Noreene DeKoning, spokeswoman for the Bureau of Collections of Investigative Services, which oversees licensing. DeKoning said it was Burns’ responsibility to determine if applicants are mentally fit for the job.

William Ewing, president of the Western states unit of Burns International, declined to comment on what background checks were done on Huston.

Dragusica said she was not concerned when her son began his new employment, believing it was a low-stress job. She also said that her son was enjoying the work. She said he came home from work one day last week and told her he had talked to Sylvester Stallone about Vietnam during the filming of the actor’s new movie, “Oscar.”

The movie was being filmed on New York Street, where arson investigators said they have narrowed their search to a 50-foot-wide area behind a facade at about the midpoint of the set.

Finding physical evidence is the most difficult task in an arson investigation, and deputies said it was compounded by the possibility that high-pressure fire hoses and Tuesday’s strong winds scattered debris containing evidence.

“It’s just a minute, slow-moving process,” Underwood said. “You shovel the debris and then you brush through it with your fingers. You are looking for literally anything out of the ordinary. . . .”