Three men and a woman died Sunday morning when a pickup struck their car from behind on Interstate 84 east of Pendleton.

The Oregon State Police says 46-year-old John C. Carlgren of Carlton has been jailed on accusations of manslaughter and driving under the influence of intoxicants.

Carlgren was behind the wheel of a westbound Dodge Dakota that allegedly struck a Chevrolet Beretta from behind, killing all four people in that vehicle.

The victims have been identified as 29-year-old Jessie Klien of Hermiston -- he was the driver -- 29-year-old Michelle Sawyer of Lynnwood, Wash.; 24-year-old William Johnson of Boardman; and 31-year-old Fred A. Young Junior, also of Boardman.

Umatilla Tribal Fire and Ambulance took Carlgren to St. Anthony Hospital in Pendleton, where he was treated for minor injuries. State troopers arrested Carlgren following his release and he was lodged in the Umatilla County Jail.

State troopers are continuing the investigation along with the Umatilla County District Attorney's Office.