CEDAR CITY, UT - The Utah Highway Patrol on Sept 21 arrested and charged tour van driver Yasushi Mikuni with 10 counts of negligent driving under the influence of a controlled substance and causing death or serious injury -- a third-degree felony, the Salt Lake Tribune reported. On Aug. 9, Mikuni was driving a van filled with Japanese tourists from Las Vegas when the vehicle crashed on Interstate 15 near Cedar City, killing three people and injuring 12. 

Each of the felonies is punishable by a sentence of up to five years in prison. Mikuni is 26 years old.

The Utah Highway Patrol alleges that Mikuni at the time of the crash was driving with traces of marijuana in his system and failed to stay in his lane. He also failed to keep adequate records, UHP said. 

In addition to the felony charges, Mikuni is charged with a count of driving with a measurable amount of a controlled substance in his system (a Class B misdemeanor), failing to stay in his lane and failing to keep his logbook current. The latter two charges are Class C misdemeanors. 

At the time of the fatal collision, the group of tourists was en route to Bryce Canyon National Park. 

Though Utah Highway Patrol investigators said Mikuni tested positive for marijuana use after having smoked the drug the weekend before the crash, they believe that driver fatigue was the principal cause of the accident. They allege that he failed to get enough sleep before making the long drive. However, the law permits prosecution if any amount of marijuana is detected. 

UHP investigators found nothing mechanically wrong with the van.