( CNN ) -- The U.S. Air Force has now identified at least 31 women as victims in a growing sex scandal , a four-star general said Thursday , and there might be more . The Air Force is broadening its investigation to `` actively seek any others that may have been affected by this , '' Gen. Edward Rice , the commander of Air Force Training , said . `` We are taking a comprehensive look not only at the cases that we know , but trying to do the best we can to assess whether or not there are other cases out there , '' Rice told reporters at the Pentagon . Rice said the Air Force had taken `` the unprecedented step '' of shutting down all recruit training for one day to give a written survey to all basic military trainees at Lackland Air Force base . The Texas base has become the focal point of the growing scandal . Air Force base reports more sexual misconduct charges . One trainer has pleaded guilty to having an improper relationship with a trainee , as part of a plea agreement . Staff Sgt . Peter Vega-Maldonado has been sentenced to 90 days in prison , 30 days hard labor and a demotion in rank and pay . In his plea deal , he also provided testimony against two other trainers who have been charged . He also said he had inappropriate relationships with 10 trainees . The scandal came to light in June 2011 , when a young female trainee came forward and accused her male instructor of assaulting her . Staff Sgt . Luis Walker now faces a general court-martial on 28 charges , including rape , adultery and aggravated sexual assault . He is scheduled to appear in court July 16 . In November 2011 , Rice says several military training instructors , both men and women , overheard a group of male instructors `` talking about incidents that were unacceptable '' and reported what they heard to superior officers . This week , the Air Force brought charges against two more instructors . Master Sgt . Jamey Crawford is accused of giving alcohol to a female trainee and having sex with her . Tech . Sgt . Christopher Smith is accused of seeking to conduct an intimate relationship with a trainee , making sexual advances toward a trainee and carrying on a personal social relationship with a second trainee . `` The basic training environment in particular is a target-rich environment for sexual predators , '' says Anu Bhagwati , a former Marine Corps officer who says the problem goes beyond one branch of service . Bhagwati says there 's no such thing as male instructors having consensual sex with young , female recruits . `` You can not do anything without requesting permission from your drill instructor . You can not use the bathroom , you can not move from left to right , you are literally in many cases a robot waiting for permission to take a step . And if you have that relationship which is based on fear and intimidation ... if that 's the person you 're asking help from , it becomes a very bizarre scenario . '' Betrayal of trust ? Allegations of rape at West Point , Annapolis . Bhagwati was a communications officer and martial arts instructor in the Marine Corps , and she said she witnessed several incidents of sexual harassment of junior female Marines . `` You are subject to every single order that comes out of that instructor 's mouth . If you 're not going to tell him , who are you supposed to tell ? And how are you supposed to get out of that unit to seek help ? '' Rice agrees . `` Personal relationships of any kind between trainees and instructors is strictly prohibited by our regulations and our instructions . '' Rice said he does not believe the investigation of 12 instructors at Lackland necessarily means a systemic problem exists across the entire Air Force training command . `` Nine of those 12 were in one unit . We have a total of nine squadrons , and nine of them came from one squadron . So in my assessment to this point , it is not an issue of an endemic problem throughout basic military training . It is more localized . '' The Air Force has relieved the officer who commanded the 331st Training Sqaudron during the time these incidents took place . He no longer runs the squadron , but `` remains in the Air Force , in 'administrative hold ' at Lackland Air Base , pending his next assignment , '' Rice said . The Air Force said 11 % of its military training instructors are women . In response to a question from CNN , Rice said , `` I will look at whether we need to hire more female MTIs , and whether we need to have only female MTIs over female trainees . '' The Pentagon estimates 19,000 sexual assaults occur each year . But only 14 % of these crimes are actually reported . And less than 8 % go to a court-martial . Defense officials say every base is supposed to have a confidential sexual assault response coordinator . Defense Secretary Leon Panetta recently announced special victims units would deploy trained professionals to various bases around the world . These independent personnel would be trained in interviewing victims and collecting evidence of sexual assaults . Female service members sue U.S. military for alleged rape , sexual assault .
Gen. Edward Rice says Air Force broadening investigation to `` actively seek any others '' One male instructor has pleaded guilty ; 11 more either facing charges or under investigation . Air Force shuts down all recruit training for one day at Lackland Air Force base to give survey . Former Marine : Basic training is `` a target-rich environment for sexual predators ''