Transcript for Teen accused of livestreaming fatal crash: A darker side of live online video
It's the disturbing video raising concerns about alarming behavior on the rise. A livestream of of the crash that killed a 14-year-old girl. Why a growing number of social media users are sharing unsafe and sometimes criminal activity. Here's ABC's Matt Gutman. Reporter: It took just seconds for this Instagram live stream to go from dangerous to deadly. The driver shockingly live streaming the aftermath. My sister is Dying. Reporter: The video sparking interest and disgust nationwide. Out of that tragic car crash in California. We begin with new details on that wreck involving sisters. Maybe even more tragic that it was being live streamed by the person who was behind the wheel. Reporter: Police say 18-year-old Adelia Sanchez live streamed this ride through central California while she was heavily intoxicated. Swerving past that black SUV, her 14-year-old sister and another teen in the car with her. But then the ride turns deadly. Police say the 18-year-old Sanchez began drifting off route 165. Then she overcorrected. The car tumbling. The three girls inside screaming. Please wake up! Reporter: Shockingly with her sister Jacqueline lying lifeless she continues to live stream. I Killed my sister. Okay? I know I'm going to jail for life. It's very disturbing to us because the callous nature of her actions both leading up to this tragedy and in the immediate aftermath. Reporter: Sanchez has been charged with gross vehicular manslaughter while intoxicated and also driving under the influence. She's being held on a $300,000 bail. If it is determined that it was at least a contributing factor to the accident that she was on her phone and she was showing this live, she could be charged with something up to manslaughter. That means sious time behind bars. Reporter: The passenger who survived the #rash, 14-year-old Manuela seja, speaking out about that horrific incident. I never thought this would happen. Reporter: These shocking incidents seemingly on the rise. People live streaming dangerous and sometimes illegal behavior on social media. I think as our technology increases we're going to see new innovative ways that people do or commit crimes. And here the technology is live streaming. I found somebody I'm going to kill. I'm going to kill this th guy right here. Reporter: In April a nationwide manhunt for the so-called Facebook killer. I'm at the point where I snapped. Reporter: Steve Stevens believed to be responsible for a random act of cold-blooded murder that he streamed on Facebook live. How old are you? Oh, man, I'm -- Reporter: Taking the life of 74-year-old Robert Godwin Sr. This man right here was a good man. And I just -- I hate he's gone. You know what I mean? I don't know what I'm going to do. Reporter: A 48-hour desperate search ensued, ending in Stevens killing himself. Looks like there's one guy down in the white car. Reporter: And just three months earlier four 18-year-olds charged with the beating and racial taunting of another teenager with special needs. That video also broadcast on Facebook live. Why you do this? Reporter: Those suspects arrested and now facing hate crimes charges. They've pleaded not guilty. When you live stream you literally now have potentially millions of people watching what you're doing. It's attention. I think people are weaponizing it to some extent. They're showing shock things to people who don't necessarily expect to see shocking things. That sense that I can shock the world I think is a power that a lot of people crave. It's now easier and easier to do that with live streaming. You should have never got in there. Reporter: More recently five teens filmed and mocked a 39-year-old man as he drowned. Ha, ha, ha. Reporter: Not a single one of them called 911. His body was found five days later. Many say those watching those horrific acts bear some responsibility also. I tell people every day that if they witness something either on the net or in person they need to contact authorities. I would like people to look at these live stream events just like they were at the event. If they see somebody being assaulted you're either going to step in yourself or immediately get law enforcement there to jump in the middle of it. Think about live stream in the same sort of view. Reporter: In Chicago authorities say as many as 40 people watched the alleged gang rape of a 15-year-old girl but not a single one of them called the police. Chicago police superintendent Eddie Johnson expressing outrage at the lack of action. It just disgusts me that people would look at those videos and not pick up the phone and die 911. Reporter: Adam moulter, the author of "Irresistible: The rise of addictive technology and the business of keeping us hooked" says watching online offers a cloak of anonymity. When you're watching something like this happening from a computer screen you're probably a long way away from the action. So psychological distance or remoteness is more likely to diminish and dampen helping behavior. Reporter: As a result of videos like these social media companies are now looking for ways to better monitor the content of their products. Facebook says it will soon have about 7,500 employees reviewing questionable content. That's about a third of the company's workforce. We need a way for viewers to flag content as inappropriate or unacceptable so we can stop a live stream midway rather than perpetuating it, allowing it to continue for ten minutes past some horrendous act. Reporter: Social media companies may be able to take videos down before they go viral. But they won't be able to put a stop to people themselves posting those videos. This really boils down to discipline, parents having very strict rules about when kids can live stream et cetera. Hard to control. I get all that. But that -- this really has to start in the home as far as monitoring or controlling or limiting this behavior. I think live streaming is causing a lot of fear, especially among parents, because kids are using live streaming in ways that aren't safe. Tech companies that are savvy will recognize that fear and they'll recognize there's a gap in the market to be filled and I think some of them are already doing it quite successfully. This is your daughter. Reporter: Verizon's product alerts parents when their teenagers are driving too fast. You can tell her to drive more like this was you'll get this. Reporter: Sprint has drive first, which sends calls to voice mail and silences alerts when a driver's going more than 10 miles an hour. Blocks and responds to texts while you drive. Reporter: And Chevy has developed the teen driver mode that mutes the radio if the front seat drivers aren't wearing their seat belts. In central California tonight Sanchez remains in jail. Her sister would have turned 15 on Sunday. For "Nightline" I'm Matt Gutman in Los Angeles.
This transcript has been automatically generated and may not be 100% accurate.