The driver of the SUV that killed two Washington high school students and injured two others while walking out during gym class has been arrested. 

William Klein, 34, of Bellingham, jumped a curb and struck four teens on a sidewalk. About 30 students from Windward High School in Ferndale were walking with a teacher when the accident happened, AP reported. 

Klein's 3-year-old son was with him in the vehicle, but neither was injured.

Shane Ormiston, 18, and Gabriel Anderson, 15, both of Ferndale, died at the scene while Michael Brewster and Kole Randall, both 17, suffered severe leg fractures, The Bellingham Herald reported.

The driver was arrested for vehicular homicide and vehicular assault, with bail set at $200,000 at an initial court hearing on Thursday.

Klein said that he fell asleep behind the wheel, but authorities speculate drug use as the cause of the accident.

Defense lawyer Michael Brodsky said that his client acknowledged regular marijuana use but added that Klein did not used pot on the day of the crash, according to Centre Daily Times. Klien also has past use of hallucinogenic mushrooms.

Authorities are waiting for blood and urine test results to verify the speculations.