NEW BOSTON, Texas—Testimony is expected to begin today in the trial of an Oklahoma State University linebacker accused of sexually assaulting a 12-year-old girl more than three years ago at an after-prom party in Texarkana, Texas.

Bowie County District Judge Leon Pesek and lawyers representing the state and the defense in the trial of Christopher Edward Collins Jr. spent most of the day Tuesday selecting a jury from a panel of 100 Bowie County residents. Nine men and three women were chosen. Three of the jurors are black, while the rest—along with one alternate juror, a male—are wh...