Diamond Reynolds is recorded on a cellphone as she recounts the incidents that led to the fatal shooting of her fiance, Philando Castile. (Eric Miller/Reuters)

Even before police detained Diamond Reynolds on Wednesday, her friends already knew why: The Minnesota woman had just live-streamed the bloody aftermath of a routine traffic stop in which an officer shot her fiance, Philando Castile, multiple times.

This was not the first death to stream live on Facebook; it wasn’t even the first police shooting to reach shocked viewers that way. But the unfiltered video, startling in its rawness, has quickly become emblematic of the way we process violence in the live-streaming age.

“I wanted to put it on Facebook and go viral so that the people could see,” Reynolds said, speaking to reporters the day after. The video would show the truth, she argued, “no matter how the police tamper with evidence [or] how much they stick together.”

It’s a radical departure from the way the public has traditionally encountered images of violence, and it has given those images — and the issues they embody — a much wider audience than they’ve historically had. Experiences once restricted to small communities can now be shared, in real time, by thousands. Traditional barriers to publishing, whether mainstream standards regarding graphic content or the demands of investigating police departments, have all but fallen before the logistical difficulty of moderating streams in real time.

Live-streaming technology, its advocates argue, has given incredible power to victims of systemic violence, both online and offline.

Since the early days of Occupy Wall Street, when the live streamer Tim Pool broadcast protesters’ forcible removal from their New York City encampment, activists have repeatedly deployed the technology as a means of documenting their experiences and communicating without mainstream media interference. In 2010, the organizers of a “Freedom Flotilla,” which attempted to deliver humanitarian supplies to the Gaza Strip, live-streamed their encounter with Israeli military forces. (Observers later credited it with shaping public opinion of the incident.) Smartphones broadcasting in real time to Livestream and UStream would later become a critical tool — for documentation as well as mobilization — in the Ferguson, Mo., protests. On Thursday, a Facebook live-streamer named Michael Kevin Bautista captured both a Black Lives Matter protest in Dallas and the exact moment when police officers at the protest came under attack.

“The overarching narrative of the Internet over the past 20 years is the continuous collapse of gatekeepers. Live-streaming is the ultimate embodiment of that,” said Jesse Hertzberg, chief executive of Livestream, a service that’s long been popular with activists and protesters. “You used to find out about something like a protest or police shooting after the fact. Now you have this ability to transport yourself to where it’s actually happening — it’s a real visceral, emotional connection.”

The hope that the right image will enact a needed change in the world has existed for the entire history of documentary image-making, especially when it comes to war. Upon viewing the Mathew Brady photos of the Civil War dead, the New York Times wrote that, “if he has not brought bodies and laid them in our dooryards and along the streets, he has done something very like it.” A photograph of Kim Phuc running for her life is often credited with changing hearts about the Vietnam War.

That anticipated power is often not fully realized. As a Globe and Mail columnist wrote this week, people thought the video of Los Angeles police officers beating Rodney King in 1991 would help to end police brutality against black people. But as Sarah Kendzior wrote, “the legacy of the Rodney King video was not justice, but sequels.”

Live streamers hope that the immediacy of their work will change that calculus. A cadre of self-knighted citizen journalists in Ferguson were instrumental not only in shaping national opinion of the nascent Black Lives Matter movement, but also in publicizing the stunningly hostile, often violent demeanor of police officers toward protesters. In fact, the mobile videos taken in and after Ferguson are largely credited with making police misconduct and racial violence a national conversation.

“I don’t think anybody would pay attention to all the advocates and all the protests but for the videos,” Phil Stinson, a criminologist at Bowling Green State University, told NPR Friday morning. “And you know, a dead man can’t talk. It used to be that police owned the narrative, and now we have another side to the story, quite often, with the videos.”

Among other things, live streams are copied and stored off a device the instant they’re broadcast, which makes it much more difficult for police to control or delete them.

And yet, despite all the promises of live streaming, the technology comes with its own  limitations and questions.

“We see the benefits of live streaming — it can activate a supportive community,” said Jacob Crawford, a co-founder of WeCopWatch, which encourages oppressed communities to observe police behavior. “But we see it as a challenge, too.”

Crawford’s group advises its members against live-streaming protests out of fear that the streams can unintentionally become evidence for law enforcement. But for those in a traffic stop who are looking for a way to document, WeCopWatch thinks a live stream is a “win-win. It’s an objective record.”

Others aren’t sure they want to sign on to live-streaming at all. Early Thursday, a debate about the ethics of sharing Reynolds’s live stream broke out on the Minneapolis Black Lives Matter Facebook page: Administrators urged members not to share the “traumatizing” video; dissenters argued that it had power and could provoke change. Some psychologists have suggested that persistent racism, expressed so tangibly by videos like Reynolds’s, can cause post-traumatic stress disorder in African Americans.

“Sharing a video of his murder is extremely disrespectful to his family as well as traumatizing and triggering to any people commonly victimized and murdered by cops (mostly black people),” one commenter on the Black Lives Matter page wrote.

“Talking, escalating and sharing is how revolutions happen,” another argued.

Above all, there hovers the little-discussed possibility that live streams are actually less unfiltered than their aesthetics would suggest — that, far from eliminating gatekeepers, this technology just transfers that power to social networks and apps. Shortly after Reynolds broadcast her live stream, the archived video disappeared from Facebook, to the alarm of the 1 million people who had watched it. The company quickly attributed the removal to a “glitch” — which doesn’t detract from how much power Facebook clearly has over the dissemination of these streams and images.

Meanwhile, Apple just recently received approval for a patent that would let third parties disable a phone’s ability to record, using a targeted infrared signal. The technology is billed as an anti-infringement tool for movie theaters and concert venues, but it’s not difficult to imagine how else it might be used.

“The access is amazing,” Hertzberg, of Livestream, said. “But it’s still important to maintain perspective.”

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