CROSBY, N.D. — A Florida man is facing three felony manslaughter charges in a crash in North Dakota’s oil patch that killed two children and their father.

Forty-nine-year-old William Koehler, of Chiefland, Florida, could face up to 30 years in prison if convicted. The Associated Press requested comment from his attorney.

The Williston Herald reports that Koehler is accused of speeding and using his cellphone moments before rear-ending a car that was stopped for a flagger at a construction zone in Divide County on Aug. 23.

The crash killed 2-year-old Shayleigh Gunderson, 8-year-old Shelly Gunderson and their father, 31-year-old Lesley Gunderson. The family lived in Noonan.