A tour bus crash in Southern California Sunday night killed at least seven people and sent 17 to hospitals.

A tour bus company involved in the Southern California crash that left at least seven people dead including a 13-year-old boy, has failed more than one-third of its vehicle inspections during the last two years, federal records revealed Monday.

The bus carrying dozens of men, women and children from Tijuana, Mexico, crashed Sunday night in the mountains about 80 miles east of Los Angeles while returning from a ski trip. Dozens of people were injured, at least five critically.

The crash left State Route 38 littered with debris, and the bus perched sideways on the edge of an embankment, its front end crushed and part of the roof peeled back. The precarious state of the wreckage has made extrication of bodies difficult.

"I saw many people dead,'' passenger Gerardo Barrientos said. "There are very, very horrendous images in my head, things I don't want to think about."

Barrientos, 28, said the driver called out to passengers to phone 911 as the bus careened before the crash. But he said no one had cell phone reception in the rugged area.

The California HIghway Patrol reported Monday afternoon that seven people were confirmed dead, reducing its previous total by one.

The San Bernardino County coroner's office identified five of the victims as: Guadalupe Olivas, 61; Elvira Garcia Jimenez, 40; and Victor Cabrera Garcia, 13, all of San Diego, and Aleida Adriana Arce Hernandez, 38, and Rubicelia Escobedo Flores, 34, of Tijuana, Mexico. It said it was still working to identify the other victims.

The Highway Patrol identified the driver as Norbert Perez, 52 of San Ysidro, Calif. He was a driver for carrier Scapadas Mágicas, based in National City, Calif. Answering the phone at the company's San Diego-area office, Sandra Navarrate said no one at the company was available to discuss the accident.

The highway was still closed Monday afternoon as investigators continued to work on the accident scene, CHP Officer Matthew Morrall said.

He said that so far, investigators have found "no information that points to mechanical defects at this time.''

The Highway Patrol said in a written statement Monday afternoon that the bus was headed downhill when the driver "experienced a loss of control allowing the front end of the bus to strike the rear of a Saturn sedan traveling within the same lane.'' It said the bus then veered into the opposing lane where it collided with a Ford pickup truck pulling a trailer.

"As a result of the collision, the bus rolled over causing several passengers to be ejected. The bus was then deflected back into the eastbound lane after striking a large boulder adjacent to the roadway. Upon striking the boulder, the bus became upright and came to a stop blocking both lanes of SR-38,'' the statement said.

Morrall said the bus passengers were on a trip from Tijuana for a day of skiing in the Big Bear mountain resort area.

Federal transportation officials on Monday launched an investigation into the crash.

Scapadas Mágicas LLC had 25 vehicle inspections in the past 24 months, and nine vehicles were removed from service, the Federal Motor Carrier Safety Administration reported. The national average is about 20%.

During the same period, the agency examined the records and credentials of 28 drivers and took one off the job — a rate lower than the national average.

The California crash came one day after dozens of people were injured when a bus slammed into an overpass in Boston.

Neither of the bus companies involved in the weekend crashes had an accident within the past two years, federal records show.

The Transportation Department has been moving faster to shut down bus companies for safety violations after a spate of fatal crashes in recent years.

The Federal Motor Carrier Safety Administration (FMCSA) closed 28 carriers as imminent hazards to safety last year, up from none in 2009.

The number of motor coach inspections has increased 15% in the last three years, to 33,684 last year from 29,401 in 2009. Among last year's inspections, the agency took 880 drivers and 1,831 vehicles out of service.

Federal policy also changed to force bus companies to fix problems faster.

Under a policy in place since 1990 allowed a 45-day period for bus companies to prove they have fixed problems, which could be followed by a 10-day extension. But FMCSA has informally dropped extensions — in part because a company Sky Express was operating under an extension when its fatal crash occurred May 31, 2011, in Doswell, Va.

Besides killing four people, the crash injured 49 others when the bus rolled onto its roof along northbound Interstate 95 on a trip from North Carolina to New York.

The National Transportation Safety Board blamed the Virginia crash on the driver falling asleep after limited rest during the previous three days. Deborah Hersman, NTSB chairman, said in July after the board completed its investigation that the crash "never should have happened."

She noted that the Federal Motor Carrier Safety Administration could review only 2% to 3% of companies each year, but visited Sky Express repeatedly. The company, which has shut down, had no safety-management system, lax record keeping and no in-service training, according to NTSB.

In May 2012, the agency shut down 26 bus companies as "imminent hazards to public safety" that transported 1,800 passengers a day along Interstate 95 from New York to Florida. The complaints focused on drivers without valid licenses, a lack of drug and alcohol testing and a lack of safety inspections.

Contributing: Associated Press, William M. Welch in Los Angeles.