LOS ANGELES -- A bonfire built by college students and never fully extinguished was responsible for the massive wildfire in Santa Barbara that destroyed 210 homes, many of them multimillion-dollar properties, authorities said Tuesday.

An anonymous tipster told police 10 students gathered last Wednesday evening at a property known locally as the "Tea Garden," next to an abandoned home in the hills of Montecito, Santa Barbara County Sheriff Bill Brown said. They built a bonfire during the night and stayed until 3 a.m. to 5 a.m. the next day.

They believed that had put out the fire before leaving but embers remained and roared to life as "sundowner winds" swept in Thursday evening.

"It appears this fire was the result of carelessness, not criminal intent," said Brown, who declined to say which school the students attend.

Though Brown said there was no "malicious intent," the county district attorney will review the case and determine if criminal charges are filed.

The fire burned intensely into the weekend, chewing up 1,900 acres, destroying 210 homes and injuring more than two dozen people, including a Montecito couple who remained in critical condition Tuesday at the University of California, Irvine, Medical Center. Lance and Carla Hoffman, both 29, were severely burned while fleeing their home, which was destroyed.

The Montecito blaze, which was named the Tea fire, was the first of three to erupt in Southern California. They collectively damaged or destroyed about 1,000 homes.

In Los Angeles County, an 11,200-acre fire in the San Fernando Valley was 70 percent contained Tuesday. About 50 miles to the south, the last remaining evacuation order was lifted in Orange County, where a nearly 29,000-acre complex of fires was 75 percent contained and some of the 3,760 firefighters were being sent home.

The worst-hit area was the Oakridge Mobile Home Park in Sylmar, about 20 miles north of downtown Los Angeles, where 484 homes were destroyed. For a second day Tuesday residents were allowed back in to salvage what they could from acres of ashes.

Los Angeles County officials sent crisis counseling teams to comfort the victims.

Meanwhile, lawmakers geared up to help those who lost their homes. President George W. Bush made a disaster declaration for California, freeing up federal aid to areas ravaged by the wildfires that blackened more than 65 square miles.

Gov. Arnold Schwarzenegger signed an executive order waiving state fees for fire victims who need to replace destroyed birth certificates and other documents or obtain state property inspections. The order also waived a one-week waiting period for unemployment insurance applicants who lost their jobs because of the fire.

Los Angeles County Assessor Rick Auerbach said his office had begun identifying damaged or destroyed homes to reassess their value and provide their owners with property tax relief.