A teen fired up Facebook Live from the highway. Moments later, everyone in her car was dead.

“Are you going live?”

It would be the final question Brooke Miranda Hughes would hear before a tractor-trailer plowed into the back of her car as it crawled down Interstate 380 in Pennsylvania just after midnight Tuesday.

Chaniya Morrison-Toomey, the passenger who posed the question, was referring to Facebook Live, which Hughes had just launched to broadcast live from her moving vehicle, according to the Scranton Times-Tribune.

The final moments of their young lives — marked by a flash of lights, screeching tires and then seven minutes of blackness — were captured on the live-streamed video after Hughes, sitting behind the wheel, held her phone near her face for the rest of the world to see.

Hughes, 18, and Morrison-Toomey, 19, were declared dead at the scene.

The driver of the truck that killed them was uninjured, according to the Associated Press.

Video of the incident, which began so innocuously, was posted on Hughes’ Facebook page, where it has been watched more than 7,000 times, according to the Times-Tribune.

[‘She got caught up in the likes’: Teen accused of live-streaming friend’s rape for attention]

Facebook Live launched in 2015 and allows users to stream live video to their Facebook pages, where others can watch in real time, or after the fact. The service is used in a variety of capacities, from broadcasting breaking news, protests and events to giving lectures or communicating with friends.

Chris Cox, Facebook’s chief product officer, told CBS News in April that Facebook Live allows users to bring “a little TV studio” to their pockets.

It was via Facebook Live that Diamond Reynolds broadcast the aftermath of the fatal police shooting of her boyfriend during a traffic stop in a Twin Cities suburb.

“Stay with me,” she told Philando Castile. Her Facebook video quickly spread across social media and cable news, turning the deadly July confrontation into one of the highest-profile fatal police shootings in recent years. Last month, prosecutors in Minnesota charged the officer who killed Castile with second-degree manslaughter.

The aftermath of this Minn. police shooting was live streamed on Facebook. Here's what you need to know.

Play Video3:30

The officer who fatally shot Philando Castile, 32, has been charged with second-degree manslaughter. Here's what you need to know about the traffic stop gone wrong, which ended up live-streamed on Facebook. (Editor's note: This video has been updated.) (Monica Akhtar, Jenny Starrs, Gillian Brockell/The Washington Post)Following the fatal crash in the Poconos this week, Samantha Piasecki, a 17-year-old friend of the two victims, told the Times-Tribune that she had been in the car with Hughes and Morrison-Toomey earlier that night. But she asked to be dropped off at her mother’s house in Scranton, before the wreck.She told the paper that she ended up watching the crash video around 3 a.m. the same night.“It broke me,” she said.“They were both down-to-Earth people,” she told the paper. “They had good personalities. They had smiles that could light up dark rooms. Anytime you were with them it was always fun.”Piasecki told the Times-Tribune that she’s guilt-ridden now because she feels like she “could have stopped it somehow” had she still been in the car.

[‘Sorry I was being stupid,’ he said in a farewell video after crashing. Then came his ‘miracle.’]

Police told the Times-Tribune that Hughes was driving slowly in the right southbound lane of I-380 when the wreck occurred.

One of the car’s wheels had been replaced with a spare tire, but it did not have a flat tire, as some early reports suggested, police said.

Police, who did not immediately respond to requests for comment Thursday, told the Times-Tribune that the investigation is ongoing.

They have not determined whether the driver of the tractor-trailer, Michael Jay Parks of Tobyhanna, Penn., will face charges.

The video, however unsettling, is not considered a violation of Facebook’s community standards, according to a Facebook spokesman.

“However,” the spokesman added, “a graphic warning screen has been added, auto-play has been disabled and it is not accessible for users under the age of 18.

“Additionally, the user’s account has been memorialized.”

Hughes was a student at West Scranton High School, according to the Times-Tribune. Her Facebook page says she worked at McDonalds.

On a GoFundMe page started to raise money for Morrison-Toomey’s funeral, she was described as having an “energetic” spirit.

“Her jokes and faces that made you laugh,” the page’s description says. “Although Chaniya was only 19 she was full of so much life, positivity, and love that she could bring anyone out of the darkest place and make you think the world was sunshine and rainbows.”

Since Facebook Live launched in April, millions have used the service to offer a glimpse into the big moments and small details of their lives.

The view isn’t always pretty.

[After shooting ex-wife and child, killer tells Facebook Live that ‘she deserved what she had coming’]

In September, a man who had just critically injured his ex-wife and fatally shot his namesake son in North Carolina made a chilling confession on Facebook Live.

“She lied on me, had warrants taken out on me,” Earl Valentine told the camera while driving on a dark road. “She drug me all the way down to nothing. I loved my wife, but she deserved what she had coming.”

Valentine acknowledged that the violent chain of events he started could end in his own death.

“Pleasure knowing all y’all,” he said. “I’ve been very sick for months. And this is something that I could not help. So I don’t know if I’m gonna make it where I’m going, but if I don’t, I wish all of you a good life.”

Within hours, authorities located Valentine at a motel in Columbia, S.C., where, they said, he committed suicide after being surrounded.

Valentine yet another example of a person using Facebook Live to discuss a violent act — or to showcase the act itself.

In June, Larossi Abballa, a terrorism suspect accused of killing a French police captain and his partner in their home, broadcast the aftermath of the attack on Facebook Live. An occasionally tearful Abballa, speaking a mix of French and Arabic, swore allegiance to the Islamic State militant group and encouraged others to follow his example and kill police.

A month later, a Georgia mother went on her daughter’s Facebook account to broadcast herself beating the teenager — punishment for posting sexually explicit pictures on the site.

“This is my page now,” Shanavia Miller told the camera after she fixed her hair. “Now I’m gonna need y’all to send this viral. Please share this because I’m not done. More to come.”

A July shooting in Norfolk that injured three men was inadvertently captured on Facebook Live. In the video, three men are sitting in a car, smoking and listening to rap music. Five minutes into the video, there’s a series of 30 gunshots.

The nascent live-streaming service is raising philosophical questions about the power of unfiltered Internet video that can reach millions instantly.

As The Post’s Caitlin Dewey wrote in July:

Facebook Live, which launched globally in April, has quickly emerged as one of the Internet’s dominant platforms for streaming unfiltered, real-time video. As Facebook has learned in the past week, however, that status comes with unique challenges.
Real-time video is exceedingly difficult to moderate, as it reaches its largest audience instantaneously and can be redacted only after that moment of impact. That limits the power of even a dedicated, 24-7 moderation team, which Facebook Live has. Despite growing concern that the tool could be abused — several shootings, a police standoff and an accused jihadist’s confession have streamed on Facebook already — the company has remained intentionally (and characteristically) vague on the composition and guidelines of its moderation team.

The deaths of the two Pensylvannia teens came shortly after a 20-year-old Rhode Island man broadcast himself on Facebook Live driving erratically and reaching speeds up to 115 mph before hitting a dump truck, skidding across three lanes and slamming into a median, according to ABC News.

In that video, Onasi Olio Roja can be seen weaving in and out of traffic, blasting rap music and yelling, “Let’s get it papi!” — moments before he totals his car.

“How lucky we are that no one else was hurt,” said Capt. John Allen of the Rhode Island State Police said. “It’s a grand slam of things not to do.”

He was charged with reckless driving and operating a suspended license and arraigned from his hospital bed over the weekend, according to CBS affiliate WPRI.

In February, an Ohio teenager pleaded not guilty after she was accused of using a different live-streaming service, Periscope, to broadcast the rape of her 17-year-old friend. Marina Lonina, 18, a student at New Albany High School, outside Columbus, was attempting to record the assault as evidence, her attorney, Sam Shamansky maintained.

“She’s in the habit of filming everything with this app called Periscope,” Shamansky acknowledged at a court hearing in April, according to ABC affiliate WSYX. “She does everything possible to contain the situation even to the point of asking while it’s being filmed to these Periscope followers, ‘What should I do now? What should I do now?’”

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Lonina faces charges of rape, sexual battery, kidnapping and pandering sexually oriented matter involving a juvenile and is due to appear in court on Dec. 12, according to the Columbus Dispatch.