Transcript for Vanessa Guillen’s remains found in shallow graves: Part 6
behind, yet they're leaving my sister behind, because clearly after two months they're trying their best to find her. After two months! The army and police are asking you to call them if you have seen her or know any information. Vanessa was last seen on ft. Hood. It's been more than a year now since Vanessa's mother, Gloria Guillen, learned the devastating news that her daughter had apparently vanished while on duty as a soldier at ft. Hood army base. How does it feel knowing that so many people who didn't know Vanessa have painted these murals, left the candles and cards and flowers? A story like Vanessa's hits close to home. As a Latina, a journalist, it's heartbreaking. We're not going to stay But Vanessa's family never gave up. The "I am Vanessa Guillen" hashtag empowered military service members to come forward with their own stories of sexual harassment and assault within the military. You see all these stories of what happens to the victims when they report something. A lot of them talk about how they were not believed, how they were criticized. This movement right now can make the positive change that we need. At that point everyone knows Vanessa's missing. 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. And then all of a sudden, some contractors are working near this same area. There was a crew working on a fence. They smelled a horrific odor. They went to investigate, and that's what triggered them calling the local sheriffs out there. Around 11:00 A.M., the bell county sheriff's department received a phone call from a citizen. He knew that there was some searching going on for the missing ft. Hood soldier. This is an area that army investigators, that volunteers, that deputies have searched. We arrived on scene, and he took us to the area. We saw what he was looking at and we did believe that it was some type of rains. 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 -- that looked human. At that point I reached out to the Texas rangers with ft. Hood Cid on the case, and notified them. Texas equusearch gets the call that they wanted us to come back. Some remains had been found. We started digging in the other areas close by where we located the first remains, and then we were able to find two more. The remains are found in three separate shallow graves, and those graves are then concealed with cement. It was sophisticated because of the way they hid her so well. She blended in with the environment. Search teams were there days before looking for Vanessa near the Leon river. They had walked over the spots where they're now saying they found her. The word did get out and media did start to show up. ABC 13 eyewitness news live at 5:00. Starting with this breaking news tonight. New developments in the search for missing ft. Hood soldier and Houston native Vanessa Guillen. When we got to the scene, it was just chaos. Authorities everywhere, reporters everywhere, cameras everywhere. And there was just this feeling of, is that Vanessa? When the remains are found, our special agent in charge actually contacts Vanessa's sister. I got call from Cid on June 30th. They just told me, we did find the partial human remains. And this time they didn't tell me it's not her. So of course I -- I started thinking the worst. And I get a second call from Tim, Tim Miller, the founder of equusearch. And he always spoke to me with the truth. I, you know -- I get choked up now. Um. I remember that day. I remember that day. Texas equusearch founder Tim Miller says investigators found a shallow grave covered by rocks. Recent rain had made it difficult to see. He did ask me, are you by yourself? Are you in a private area? And I said, you know, whatever you have to say, you can tell me. I said Vanessa's been found. There was a lot of silence after that one. A lot of silence. I just couldn't believe it. And the way that he knew that it was Vanessa was because he described her hair to me. And I just dropped my phone, and it was just like everything came to an end. I was actually at a restaurant. I was with my friends. You know, they were trying to cheer me up. And out of nowhere, all the TVs went red, and they said, breaking news. The army tonight telling the grieving family of Vanessa Guillen that remains found last week are indeed her. I just started crying. The focus really shifts to specialist Aaron Robinson, because at this point he's the prime suspect in Vanessa's murder. 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 for the next 24 hours. Why couldn't he simply be arrested and charged at that point? That's an area that you have to scratch your head. You would think someone would make the command decision, we're going to make an arrest. These soldiers are tasked with watching Aaron Robinson in shifts. Army officials say that there's a text thread between a supervisor and the soldiers. The supervisor tells them if specialist Robinson tries to leave, tackle him, immediately call military police. So while Robinson is being watched by those soldiers on the base, officers track down his girlfriend Cecily Aguilar, and they say this time she has a very different story to tell. What investigators say happened out there on the Leon river is so terrible, it's almost hard to fathom.
This transcript has been automatically generated and may not be 100% accurate.