Prosecutors allege Graham shot 16-year-old Adrianne Jones, a high school classmate with whom he'd had a romantic relationship, because his jealous girlfriend, Diane Zamora, told him to. If convicted, Graham would face life in prison.
The trial, with jury selection scheduled to begin Monday, was moved from Fort Worth to New Braunfels, 30 miles northeast of San Antonio, because of intense publicity.
Zamora, a former Naval Academy cadet, was convicted in February in Fort Worth and sentenced to life in prison. At the request of the victim's family, prosecutors are not seeking the death penalty in either case.
Besides moving the trial, Judge Don Leonard also issued a gag order.
Perhaps the most damaging item for Graham is a confession he spent two hours typing while detained in a military lockup in Colorado nine months after the Dec. 4, 1995, slaying.
According to the statement, Zamora hid in the back of her parents' car while Graham, her high school sweetheart, drove Jones to an isolated lake. Then Zamora hit Jones over the head with a dumbbell weight, and Graham allegedly shot Jones when she tried to flee.
Prosecutors contend Zamora became jealous after Graham admitted to having a one-time fling with Jones and ordered him to kill the girl.
The two weren't arrested until the following September after they'd both left Texas to attend their respective military academies.
Confiding in another Naval Academy midshipman, Zamora admitted to the slaying and described Jones as a "tramp" who "deserved to die," according to testimony.
Though defense lawyer Dan Cogdell tried to exclude Graham's confession from the trial, the judge ruled in an April hearing it was admissible.
Cogdell told The Dallas Morning News that a new prosecution witness and former teammate of Jones will testify that she, not Graham, drove Jones home, casting doubt on Graham's confession.
By Kelley Shannon