US federal investigators are nearly completing their work on scene investigation on the tour bus crash that killed six Chinese tourists and their tour guide over a week ago in Arizona, an official of the National Transportation Safety Board (NTSB) said in Las Vegas Saturday.

But the final report of the fatal accident, which had become a headline on both U.S. and Chinese news media for past week, would be anticipated within one year from now, Pete Kotowski, who is in charge of the NTSB investigation, told a press conference in Las Vegas.

The tour bus carrying a group of 15 Chinese tourists overturned on U.S. 93 highway in Arizona, about 40 kilometers south of the Hoover Dam at around 4 p.m. on Jan. 30, when returning to Las Vegas after a one-day trip to the Grand Canyon.

Kotowski said that 15 of the 17 people aboard were ejected from the vehicle during the crash because there were no seat belts for passengers in the 30-seat bus. U.S. law doesn't require seat belts for bus passengers on highways.

Nine Chinese tourists and the bus driver were injured in the crash. Most of them are still under treatment at two Las Vegas hospitals.

Kotowski said that the 48-year-old bus driver told investigators that he was distracted by the vehicle's door, which was briefly open for non-disclosed reasons just minutes before the crash occurred.

Some witnesses told investigators that they saw the driver trying to close the door when he lost control of the vehicle, Kotowski said.

But the NTSB investigators noted that the investigation has found that the door was mechanically functioning as designed.

"No conclusion has been reached for more investigation at this stage," said Kotowski.

According to him, officials of the Arizona Department of Public Safety were discussing with prosecutors on whether to file criminal charges against the bus driver, who was appropriately licensed.

(Xinhua News Agency February 8, 2009)