Vanessa Guillen's body is found, her story prompts military reform: Part 2

Her remains were found two months after she'd vanished. An independent review panel found failures of leadership at Fort Hood and a permissive environment toward sexual assault and harassment.
8:07 | 06/12/21

Coming up in the next {{countdown}} {{countdownlbl}}

Coming up next:



Skip to this video now

Now Playing:


Related Extras
Related Videos
Video Transcript
Transcript for Vanessa Guillen's body is found, her story prompts military reform: Part 2
find her, after two months. Reporter: 20-year-old Vanessa Guillen, active duty soldier at ft. Hood, Texas, has disappeared without a trace. Investigators have searched. They've been to the Leon river. They've used a number of techniques to try to find Vanessa, with no luck. Then all of a sudden some contractors are working near this same area. They smelled a horrific odor. They went to investigate. And that's what triggered them calling the local sheriffs out there. We arrived on scene, and we did believe that it was some type of remains. Some type of concrete substance was poured over the remains to try to hide it. But there was a lock of hair that was sticking out that looked human. It was sophisticated because of the way they hid her so well. She blended in with the environment. Reporter: The army wants to detain Aaron Robinson, but they don't want him to know why. Instead, they tell him a story, that he's violated covid-19 quarantine protocols and needs to stay under watch the next 24 so while Robinson is being watched, officers track down his girlfriend, Cecily Aguilar. Cecily Aguilar did tell us specialist Robinson told her that he killed Vanessa. As Aguilar's interview continues, she tells them Aaron Robinson confessed that her that he had bludgeoned a female - soldier to death in an armory room on base, and then placed the remains inside a plastic tuff box reserve if you go into the arms room and shine Luminol, it would have been a spectacular showing of blood. And that alone should have focused them in that one place that one person. According to a criminal complaint, Aguilar agrees to help Robinson get rid of Vanessa's body. They've allegedly decided to use some type of tool. Reportedly a machete of sorts. To then dismember the body. Reporter: Three days later, April 26, investigators say they come back again, bringing hair nets, gloves, and concrete. They allegedly go to the remains, attempt to further break up the body. Burn it. Then decide to cover up the body with concrete. Reporter: As Robinson sat under guard in an army conference room, he was allowed to talk on his cell phone with his girlfriend, unaware she was already talking to authorities. They essentially say, hey, we need your help, we need to call him, we need to tape this conversation. And during that call, Robinson doesn't deny anything. In fact, according to authorities, during these calls, Robinson actually texts Aguilar news articles about those remains recovered by the Leon river. At around 10:00 P.M., Robinson is heard talking on the phone, apparently to his mother, saying, don't believe what you hear about me. Moments later, he rushes out of the room. He gets in a vehicle, and he flees. And he leaves ft. Hood. And there is this incredible scene in the middle of this street where they're trying to after Aaron Robinson. They converge on him. He feels the pressure's on. He's being surrounded by law enforcement. He pulls out a gun. He shoots himself. And dies by suicide. We want justice! A federal judge denied bond for Cecily Aguilar today. Aguilar charged with conspiracy to hide and destroy evidence. She pleads not guilty. Reporter: Aguilar's lawyers have filed a motion to throw out the case. They've filed a motion to suppress the statements officers say she made. They claim Aguilar was in custody and should have been read her Miranda rights sooner. They don't concede any of her statements are accurate. But prosecutors say Aguilar spoke to law enforcement voluntarily and was not in custody. Her next court appearance is June 16th. An independent review panel looked at the command climate at ft. Hood. The findings of the committee identified the command climate at ft. Hood that was permissive of sexual harassment and sexual assault. The committee found that the criminal investigative division detachment workforce was unstable, underexperienced, overassigned, underresourced. Reporter: And then in April, a command investigation detailed mistakes and missed opportunities in the army's criminal investigation, - including an admission that Vanessa had been sexually harassed. Though not by Robinson. I was astonished that they had so much information and details. In all, 21 army leaders have been disciplined as a result of both the independent review and command investigation. Reporter: My colleague John Quinones sat down with major general Eugene labeouf, the first time he's addressed the investigation on camera. 11 of those 21 have been removed from their positions permanently. Was this a botched investigation by the U.S. Army? No. We don't believe so. Because we were able to find probable cause to link specialist Robinson to the disappearance and death of specialist Guillen. You have to admit that early on in the investigation, there were too many mistakes, too many blunders. The investigation revealed that there were errors that occurred. We'll never forget Vanessa Guillen, Joh there's a gate named ava nessa Guillen at ft. Hood, Texas. Today action one year ago, was the last time my family and myself saw her alive. Everyone that passes through that gate will see my sister's name, my sister's picture, and remind themselves about how sexual harassment and assault has to be taken seriously and about the way she was murdered. There is a seismic change at ft. Hood in terms of the way they are treating their soldiers. I know I can go back to the Guillen family and let them know that progress is being made and Vanessa was a part of that change. I am Vanessa Guillen. I am Vanessa Guillen. I am Vanessa Guillen. I am Vanessa Guillen. I am Vanessa Guillen. I am Vanessa Guillen. I am Vanessa Guillen. to make a change When we come back, a final thought. That lasts, Try Microban24 Bathroom Cleaner. Simply spray and wipe away to easily dissolve soap scum, and kill 99.9% of viruses and bacteria initially. Then reapply and allow to dry on tile to prevent mold and mildew growth for 7 days, or on countertop surfaces to keep killing bacteria for up to 24 hours. Try Microban24 Bathroom Cleaner. Brand Power. Helping you buy better. You love rich, delicious ice cream. But your stomach doesn't. That disagreement ends right now. Lactaid ice cream is the creamy, real ice cream you love that will never mess with your stomach.

This transcript has been automatically generated and may not be 100% accurate.

{"duration":"8:07","description":"Her remains were found two months after she'd vanished. An independent review panel found failures of leadership at Fort Hood and a permissive environment toward sexual assault and harassment.","mediaType":"default","section":"ABCNews/Nightline","id":"78236721","title":"Vanessa Guillen's body is found, her story prompts military reform: Part 2","url":"/Nightline/video/vanessa-guillens-body-found-story-prompts-military-reform-78236721"}