Authorities in northern California say a tour bus that had already crashed once Sunday drifted off a freeway and overturned, killing at least one person and injuring 30 others. 

California Highway Patrol Officer Jeff Borgen told the Associated Press that the bus was traveling from Los Angeles to Pasco, Wash. when the accident occurred approximately 100 miles south of the Oregon border at around 7:30 a.m. local time. The bus rolled over and came to rest upside-down on a frontage road.

Authorities did not immediately identify the passenger who died in the crash, but said that he was a 33-year-old man from Parlier, Calif. Two dozen others from the bus were taken to hospitals. Most had minor injuries and were treated and released.

Earlier in the same trip and about 50 miles to the south, the bus had struck a Denny's restaurant in Red Bluff, Borgen said. No one was injured in that crash.

Three of the injured patients were in critical condition, including one who was flown by helicopter to Mercy Medical Center in Mount Shasta with severe head injuries, hospital spokeswoman Joyce Zwanziger told the Sacramento Bee.

Three people were in serious condition at the same hospital's Redding location, where most of the patients were taken, spokeswoman Heather Nichols said.

"We drill for this kind of thing," Nichols told the Redding Record-Searchlight.

The bus, a 1996 Vanhool, was driven by Jose Victor Garcilazo, 67, of Los Angeles.

Investigators said evidence at both crash sites show that driver fatigue may have been a factor. They did not say whether drugs or alcohol may have been involved or whether any citations or charges were planned.

It wasn't clear how much damage was done in the initial crash or why the bus continued on its trip. Red Bluff police, who investigated the first crash, had no additional information on it Sunday night.

The bus operator, Yellow Arrow LLC, is based in Othello, Washington. It has a current license and before Sunday had no reported accidents in the past two years, according to federal records.

No one answered several calls from The Associated Press to a telephone number for the company that was listed in the records.

The hospital was working with the Salvation Army and the Red Cross to assist patients who had been released, many of whom were staying at a hospitality house run by the medical center.

"We're just keeping them safe and comfortable," Nichols said.

The Associated Press contributed to this report.