Court-martial in Air Force sex scandal to begin (AP) SAN ANTONIO - Military officials say the initial flirtations that Staff Sgt. Luis Walker directed at the women he trained at a Texas Air Force base became something more sinister: threats and intimidation that led to sex and eventually rape. Walker is among 12 instructors at Lackland Air Force Base in San Antonio who are being investigated in a widening sex scandal that has rocked one of the nation's busiest military training centers. Walker's court-martial is scheduled to begin Monday. He faces the most serious charges in the case - 28 counts, including rape, aggravated sexual contact and multiple counts of aggravated sexual assault. He could get up to life in prison and a dishonorable discharge if convicted. The 10 female recruits Walker is accused of either sexually assaulting or engaging in inappropriate sexual conduct with are expected to testify during the court-martial at Lackland. A seven-member jury made up of military personnel will decide the case. At least 31 female trainees have been identified as victims in the sex scandal. Air Force IDs 31 victims in widening sex scandal Courts-martial set in Air Force sex scandal Widening sex scandal rocks Texas Air Force base Officials at Lackland are calling Walker's court-martial the "cornerstone case" in the ongoing investigation. "We haven't had a case of this magnitude, certainly in recent memory," said Brent Boller, a spokesman for Joint Base San Antonio, which operates Lackland. Walker's civilian attorney, Joseph Esparza, declined to comment. The start of the court-martial Monday is expected to mostly deal with procedural matters. Testimony in the case is not likely to begin until Tuesday. The sexual misconduct at the base apparently began in 2009, but the first woman didn't come forward until last year. The first allegations were levied against Walker, who is accused of crimes that allegedly took place between October 2010 and January 2011.