A Lackland Air Force instructor along with 11 other instructors face sexual assault charges in one of the largest scandals to rock the base, one of the nation's busiest military training centers located in San Antonio, Texas.

Ten female recruits are expected to testify in the court martial trial Monday of Staff Sgt. Luis Walker at Lackland Air Force Base. They claim that Walker threatened their military careers if they did not comply and engage in inappropriate acts of sexual conduct up to and including rape.

 He is the first to stand trial for his alleged crimes. He faces up to 28 counts including rape, aggravated sexual contact and multiple counts of aggravated sexual assault.  If convicted, Walker could suffer a dishonorable discharge and up to life in prison.

There have been a total of 31 female victims identified and associated with the scandal. In a Evidentiary Hearing on June 28, 2012, a fellow airman testified that Air Force Staff Sgt. Craig LeBlanc, who is charged with aggravated assault and obstruction of justice, allegedly bragged about "getting laid" by a trainee in a supply closet.

The Air Force believes the sexual misconduct apparently began in 2009, but that the first victim came forward only a year ago, said Gen. Edward Rice, Commander of the Air Education and Training Command.

The first allegations were brought against Staff Sgt. Luis Walker, who faces the most serious charges in the court martial hearings on Monday. As of June 28, he had yet to enter a plea.

The majority of the instructors under investigation were in the 331st Training Squadron. Rice said the commander, Lt. Col. Mike Paquette, has not been accused of misconduct, but was relieved from his post because of the "unacceptable level" of misbehavior in his unit.

"In my assessment to this point, it is not an issue of an endemic problem throughout basic military training," Rice said. "It is more localized, and we are doing a very intensive investigation on that squadron to find out what exactly happened and why."

Lackland Air Force Base is the main training facility to every Airman that reports for basic training, which is currently around 35,000 per year. One in five of those in training are female who endure eight weeks of training by 90% male instructors.

Rice stated to his knowledge, all of the 31 female victims identified by investigators are have remained in the Air Force.

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