CEDAR CITY, Utah (Kyodo) — A bus carrying 14 Japanese tourists rolled off a highway in southern Utah on the evening of Aug. 9, instantly killing three of them who were ejected from the vehicle and seriously injuring seven other passengers, local police said Aug. 10.

The three fatalities were Hiroki Hayase, a 20-year-old man from Osaka Prefecture, along with a 38-year-old man and a 40-year-old woman from Tokyo whose names are being withheld until their families are informed, according to the Utah Department of Public Safety.

The police have indicated, based on witness accounts, that the vehicle’s driver, a 26-year-old Japanese resident of Las Vegas, Nev., whose name is also being withheld, may have fallen asleep at the wheel before the crash.

A local police official told Kyodo News that prosecutors are considering charges against the driver.

The small bus, registered to a transportation company in Salt Lake City, Utah, crashed four miles north of Cedar City en route from Las Vegas to Bryce Canyon National Park, a popular tourist destination, the local police said.

The seven seriously injured people were taken to three different hospitals in Salt Lake City, according to the state public safety department.

They were identified as Tomoko Mizutani, 27, Emiko Mizutani, 27, Akemi Hayase, 46, Mariko Hayase, 14, Kei Maeda, 29, Mai Hatta, 29, and Yoichi Aizaki, 60. The remaining four passengers and the driver suffered minor injuries and were sent to hospitals in Cedar City.

The bus crashed into the central divider of the highway around 6:40 p.m. Aug. 9 before rolling off the road. Pictures taken by the local media show that the bus had rolled completely over and was totaled.

It was a single-vehicle crash on a straight road with a good view, and there was no trace of braking, according to the police.

At a news conference, a Utah state police official said the driver told the police that he does not remember anything about the time when the accident occurred.

Among the 14 Japanese tourists, eight were traveling in a group tour organized by Nippon Travel Agency Co., four were clients of major travel agency H.I.S. Co. and the remaining two were Kinki Nippon Tourist Co. customers, according to the agencies.

The tourists departed from Narita airport Aug. 8 and were to return to Japan in about a week. The travel agencies consigned the round-trip tour from Las Vegas to other sightseeing spots around there to a tour company in Utah.

Nippon Travel Agency said that all three of the fatalities were among its eight clients, between the ages of 14 and 52. The other five are two from Aichi Prefecture and three from Osaka Prefecture.

“This is truly heartbreaking,” Nippon Travel Agency President Kazuaki Maruo said at a press conference on the evening of Aug. 10 in Tokyo. “We feel very sorry” for what happened in Utah, he said.