LOS ANGELES – Federal regulators on Friday ordered a tour bus operator involved in a Southern California crash that killed eight people to immediately stop operating because its buses weren't properly maintained or inspected and its drivers weren't properly vetted for qualifications.

The Federal Motor Carrier Safety Administration said in a statement that it ordered all three buses operated by National City, Calif.-based Scapadas Magicas LLC in the U.S. to stop operating because they pose an imminent hazard to public safety.

The roadworthiness of the 1996 bus involved in the Feb. 3 crash has been in doubt after the driver said the brakes failed before it smashed into a sedan, flipped, slammed into a pickup and crashed on a road in the San Bernardino Mountains east of Los Angeles. The bus was carrying 38 people, including the driver and a tour guide, to Tijuana, Mexico.