BELLINGHAM, Wash. — An SUV jumped a curb and plowed into a group of Washington state high school students out for a gym class walk on Wednesday, killing two boys and seriously injuring two others, the Washington State Patrol said.

About 30 students from Windward High School in Ferndale, north of Bellingham, were out walking with a teacher along a sidewalk when the vehicle left the road and hit the four teens, Trooper Mark Francis said.

The 34-year-old driver, who had his 3-year-old son in the vehicle with him, was arrested. Neither he nor his son was hurt. The man initially said he fell asleep at the wheel but later acknowledged he had used drugs, Francis said.

Some classmates walking behind those who were struck watched the crash happen, Francis said.

“Just heard just the worst yell – just, ‘No! No! No!’” Shelley Hardt, who was working nearby, told KOMO-TV. “You knew that something really, really bad had happened. So I ran outside as fast as I could.”

Lynnette Delamare and her husband live nearby and had watched the teens walk by. Then they heard three or four loud crashes from the street.