Transcript for Explosive items found in and near high school after deadly shooting: Police

Tonight a horrific school shooting back home. The images playing out on TVs even in the uk. In Santa fe high school a student opening fire. First responders race to the school. At least ten dead, the victims students and a teacher. Those who got out another in fear and grief. Anxious parents praying they would see their children again. ABC' Tom llamas on the scene with how the horror unfolded. He was shot! Reporter: The horror unfolding just as school was getting underway. The rampage started. Students sprinting to safety. Go! Go! Reporter: Teachers hustling them the scene it began around 7:40 A.M. Senior Tyler turner says his friend spotted a boy with a gun. He saw the kid walking down the hall, he looked suspicious and whatnot. He said he had a gun or something. So he went down the hall, walked down casually. Didn't want him to know. And then pulled the fire alarm and we all went outside and we heard three shots. Reporter: That fire alarm driving students from their classrooms. As soon as the alarms went off, everybody just started running outside, and next think you know, everybody looks and you hear -- boom, boom. And I just ran as fast as I could to the nearest forest, so D hide. And I called my mom. Reporter: Police racing to Santa fe high school. He's actually shooting. He's in the art room. We've got shots -- shots fired right now, guys. Reporter: Student Peter matuza tells Marcus Moore he was right there when the shooter unloaded. He opened fire with a shotgun and shot one of my other friends in the head. Her body fell down not too far from where I was. He turned and opened fire with the revolver. Reporter: Kids lining up on the field opening backpacks for officers to inspect. They were patted down. With students shaken outside others hiding in classrooms. Their parents getting the dreaded phone call. She called. She said, "Mom, there's shots." I turned around, I said, "I'm coming, I'm coming." Stayed on the phone with her the whole time. Just kept talking to her, kept telling her to stay calm, stay quiet, until the police finally let her out. Reporter: By 9:00 A.M., the shooter had surrendered, but the danger wasn't over. The suspect wanting to take his carnage to a new level of evil. There have been explosive devices found in the high school and areas adjacent to the high school. Reporter: Tonight, 10 people dead, most of them students. Others wounded in the hospital. And now the suspect has a mugshot -- 17-year-old dimitrios pagourtzis, a junior at Santa fe high school. On Facebook, he's in a baseball cap with a peace sign. But about three weeks ago, he posted this photo of a shirt with the words born to kill. Authorities say he kept extensive journals. Not only did he want to commit the shooting, but he wanted to commit suicide after the shooting. As you probably know, he gave himself up and admitted at the time he didn't have the courage to commit the suicide. Reporter: Police say he used two guns -- a shotgun and a .38 revolver. They belonged to his father. But they have no theories yet on what drove him to open fire on his classmates. Their stories now all too familiar. I was very, very scared. I had to have someone keep me calm. I managed to keep calm though it all. Was there a part of you that was like, "This isn't real? This would not happen in my school?" No, there wasn't. Why so? It's been happening everywhere, I've always kind if felt like eventually it was going to happen here too. Chilling to hear her say she thought it would happen at her school. I want to bring in Tom llamas. He's on the scene. We know the suspect is in custody. The police interviewing two persons of interest. That's right David. This is coming from the governor of the state of Texas. He said one person was on the scene and had a suspicious reaction to events and another person they want information from. This is the family reunification center. This is where parents are picking up their children. You have to understand there are a lot of parents who have a lot of unanswered questions. Tonight we can report one of the victims was a teacher.

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