Authorities in Grant County have released the names of four people who were killed in a two-vehicle accident involving a semi-truck north of Royal City earlier this week. The driver of the sedan, 34-year-old Martin Tran, and three passengers in the vehicle, 39-year-old Thomas Tran; 66-year-old Theresa Tran; and 69-year-old Joseph Tran, all of Tacoma, were killed in the collision. A fifth passenger in the sedan, Michael Tran, whose age has yet to be verified and also of Tacoma, was critically injured in the accident and airlifted to Kadlec Medical Center in Richland for treatment. The driver of the semi, 68-year-old Felipe Alvos, and three passengers in his vehicle, 71-year-old Rosa Amador, and two children, ages 6 and 7, all of Walla Walla, sustained non-life-threatening injuries in the crash and were transported to Samaritan Hospital in Moses Lake for treatment. Sheriff's spokesperson, Kyle Foreman, told KPQ News on Wednesday (July 29) there's no indication that intoxicants or excessive speed on the part of Alvos were contributing factors in the collision, but the incident remains under investigation.