Texas Air Force Instructor Gets 20 Years in Prison The women assaulted by their Air Force training instructor don't sleep much these days and when they do, he sometimes haunts their dreams. They testified Saturday about being suddenly unable to relate to husbands, boyfriends and even fathers and brothers after they were sexually assaulted. One said her fear during a tour of duty in Afghanistan was heightened by soldiers who reminded her of her instructor, and she warned her younger sister not to enlist in the Air Force. Another said she's now afraid to be behind closed doors with any man. Staff Sgt. Luis Walker was sentenced to 20 years in prison Saturday for crimes that included rape and sexual assault. He is among 12 instructors investigated for sexual misconduct toward at least 31 female trainees at one of the nation's busiest military training centers. Six have been charged with crimes, and the counts against Walker were the most severe. He could have faced life in prison. Prosecutors say he used his position as a military trainer at Lackland Air Force base in San Antonio to gain female recruits' trust, and then he made illicit sexual advances. Walker's court-martial included testimony from 10 women, one of whom wept as she described him luring her into his base office and sexually assaulting her on a bed, ignoring her pleas to stop. Air Force Staff Sgt. Luis Walker, left foreground, arrives for the fourth day of his trial at Lackland Air Force Base in San Antonio, Texas, Friday, July 20, 2012. Walker showed little emotion as the sentence was read, but he appeared to have tears on his face later as he gazed at his wife, Yeimi. Both had cried earlier, while asking the military jury for leniency and a shorter sentence so that he would be able to spend time with his two sons, ages 7 and 4. "I ask for my family's sake, for my two boys right there," Walker said, wheeling around to look at the youngsters, who sat squirming and chattering back and forth with no understanding of the proceedings. Walker's stepfather, sister and wife all testified on his behalf, describing an earnest teen who grew up in a tough corner of Brooklyn, dreamed of joining the Air Force from the age of 14 and arranged to graduate from high school early so he could enlist. "All of his dreams are shattered and our dreams because I was so proud of him," said Herbert O'Connor, Walker's stepfather. Walker was taken after the hearing to a temporary lockup at Lackland to await transfer to a permanent prison. The six men and woman who served on the military jury are barred from discussing their deliberations so it's impossible to know if the testimony swayed. But the victims' testimony was equally as emotional. Five spoke during sentencing, including four who are still in the service. "In Afghanistan, I was a little bit more scared of everything," said one, who said Walker sexually assaulted her last year, while she was a trainee at Lackland. "I couldn't work with certain individuals," she added, "just since they remind me of Staff Sgt. Walker." Prosecutors say Walker sexually assaulted or had improper sexual or personal contact with at least 10 female recruits from October 2010 through January 2011. The Associated Press does not usually identify victims of sexually assault. The same victim said her 15-year-old sister talked about joining the Air Force, and "I've absolutely told her she's not allowed anywhere near" it. Other victims said they had the same advice for female relatives and friends.