Transcript for Video shows actions and inactions of border officers resulted in tragic 2013 incident
Tonight the video the government didn't want you to see, showing a disturbing encounter between two U.S. Customs officers and a teen from Mexico. Within hours the teenager dies and the video appears to conflict with what officers say led to his death. It's an exclusive ABC news investigation, and ABC's chief investigative correspondent Brian Ross starts us off tonight. Reporter: It's 6:21 on a Monday evening at the San ysidro, California border crossing. And the man in the white sweatshirt is a smuggler. A 16-year-old high school student by the name of Cruz Velasquez, with drugs hid nen two bottles in his shoulder bag. Cruz was recruited, we believe, as a mule. Here, we'll give you $100 or $200 if you just take these bottles across the border. Reporter: Over the next one hour and 38 minutes this video obtained by ABC news will show in gripping detail just how far U.S. Border officers will go, encouraging or at least permitting this teenager to prove his innocence by drinking from a suspicious bottle, an encounter that will end up as a matter of life and death on the border. There is a clear history of agents and officers engaging in what I believe was serious misconduct. Reporter: And our ABC news investigation conducted with the non-profit investigative fund found that despite more than ten suspect deaths and hundreds of other allegations of misconduct and threats border officers and agents are rarely prosecuted or even punished. Within that large organization are many who believe they're held to a different standard and won't be held accountable for engaging in misconduct. Reporter: Often misconduct reported by young people, children and teenagers traveling without parents whose complaints are given short shrift. Translator: He told me to take off my bra, and he started touching me. Reporter: Just last year knees two site these two sisters who had fled Guatemala to seek asylum in the U.S. Say they were violated one after the other by a U.S. Border agent supposedly searching for contraband. Translator: The agent came back with my sister and then said to me, "It's your turn." Then he said "Pull down your underwear." He reached his hand out and put his hand in between my legs. And the worst was when he told me turn around, bend over. And I bent over. Reporter: But their complaint like scores of others according to the aclu was quietly closed when the agent simply denied he did anything wrong. He said, they said, and he was the one who was believed. They just take the agent's word for it. That's correct. Reporter: Mibda works in the aclu's border program in San Diego. If the agent says I have no knowledge of this? That's it. That's it? I don't remember that. These are just some of them. Hundreds and hundreds of complaints filed by unaccompanied minors to your own agents. Reporter: Gill karlakowski, the commissioner of customs and border protection under the Obama administration, says the complaints only involve a small number of officers and agents. These don't trouble you? Well, the number of complaints that come in are high. But I'd say under my watch we've increased dramatically our ability to do these investigations. So you don't see any cover-up of allegations by you or anyone in this agency? I don't see any cover-up especially by me. Reporter: In the wake of our questions customs and border protection now says the complaint filed by the two sisters is not closed but remains under investigation. Which the aclu says will make it a first in over 100 cases their lawyers have analyzed. As far as I can tell, there hasn't been a single complete investigation on any of the allegations that I've seen. Reporter: In the case of Cruz Velasquez, his encounter with customs and border protection went bad almost immediately as he came face to face with officers Adrian peryoung on the right and Valerie Baird on the left. The young man appears nervous, and the officers start to examine the two bottles in his bag. So they know that there's something funny, there's something fishy. Reporter: What's in the bottles is highly concentrated methamphetamine, dissolved in liquid. And instead of doing a standard field test the officers will make a decision that the family lawyer gene Iredale calls outrageous as he takes us through the video. Cruz now points at the bottle and she's saying, okay, drink it. And she makes the gesture that we associate with to drink. Now, watch the male agent. He says drink another one. You see them exchanging glances and smiles because they know what's going on. This is a game in which he's being played with by these officers. They want to see what his reaction is. Reporter: Velasquez knows he is in trouble and not just with the border officers but also with the ruthless bosses of the cartel who paid him and do not tolerate failure. In his mind the cartel is worse than the U.S. Agents. Reporter: Former FBI agent Steve Gomez, now an ABC news consultant. A lot of times they don't even want to hear the excuse. They'll just kill everybody and make an example. So he's in a bad place. A very bd placad place. Reporter: Now at 7:07 P.M. Two minutes after the first drinks it happens again and again. Two more sips. And you see the smile. Reporter: A total of four swallows in all of the highly toxic solution. Something the officers will later say under oath the teenager volunteered to do with no prompting from them and before they had any suspicions about what was in the bottles. I never asked him to. He volunteered to. And I believe I gestured to him to go ahead. You told him to go ahead and drink on more than one occasion, did you not? No. You're sure of that? I'm sure. Reporter: But the government video obtained by ABC news seems to contradict that. Now taken in handcuffs to a security office Velasquez can barely stand. Sweating profusely, upsetting officer Valerie Baird. I noticed some labored breathing, and he was shaking a lot. I remember putting my hand and just told him to like relax. Reporter: It will be more than 35 minutes after the first drink before officers call for a team of paramedics. A fateful delay. Because the drug's making the heart beat so fast, the heart needs more oxygen. It essentially can't get enough oxygen. As a result the person develops chest pains. Very similar to if they were having a heart attack. Reporter: Now at 7:51 a San Diego fire department team of paramedics does arrive. He is handcuffed to a gurney for a trip to the hospital. His temperature rising to 105 degrees. His heart racing at an incredible 220 beats a minute. What do you think he's feeling at this point? Abject terror. Abject terror? Absolutely. Reporter: According to the San Diego county medical examiner, 16-year-old Cruz Marcellino Velasquez Acevedo died at 8:57 P.M. Of acute methamphetamine intoxication, less than two hours after he first drank from the suspicious bottle. You felt guilty that Mr. Velasquez died, didn't you? No. No? Didn't you cry? I did. Yes. Did you not feel guilty that he was dead? No. He's not without fault. He was doing something he ought not to have been doing. The issue is in such a circumstance is the death penalty and a death that was so quick and cruel, is that deserved? He cooked within his own body, and he died in terrible pain. Reporter: But within hours of his death the official report prepared that night with input from the officers' colleagues said the manner of death is an $- accident and that Velasquez voluntarily took a drink from one of the bottles. Actually, it was four drinks. Despite what the video appears to show, the officials at customs and border protection apparently believed the claims of the two officers instead. Officer perallon, was any discipline ever imposed upon you for the events that occurred on the 18th of November, 2013? No, sir. Even as a result of the death of Cruz Velasquez Acevedo no discipline was ever imposed on you, was it? No. Not even a reprimand? No. Not even a reprimand? I've never gotten a reprimand. No. The two officers remain on duty to this day. So what's the message that sends to other agents? Well, it's a very simple lesson. Do what you want. So long as the person who's hurt doesn't have political power or juice, doesn't speak English, from a foreign country, have a good time. Reporter: Earlier this year the government paid the family of Cruz Velazquez $1 million to settle the lawsuit they had brought. There was no apology and no admission of any wrongdoing. For "Nightline" Brian Ross, ABC news, San ysidro, California.
This transcript has been automatically generated and may not be 100% accurate.