The driver of a car that crashed in northern Colorado last week, killing three people, apparently fell asleep behind the wheel.

Twenty-two year-old Anthony Alacca of Cheyenne has been charged with three misdemeanor counts of careless driving causing death and one misdemeanor count of careless driving causing injury in a crash, that occurred on Thursday, August 15th, just before dawn.

A brother and sister, 21-year-old Michael De La Rosa and 18-year-old Mariah De La Rosa, and 21-year-old Michael Gnoato died after Alacca failed to negotiate a curve on U.S. Highway 85, about 10 miles south of the Wyoming border.

The sedan hit an embankment, went airborne and rolled.

A fourth passenger, 21-year-old Mariah Motschman, was injured and remains in critical condition at North Colorado Medical Center in Greeley.