The videos are horrifying to watch.

Less than 24 hours after the public watched video of police killing Alton Sterling outside a convenience store in Baton Rouge, La., a Facebook Live video recorded by Diamond Reynolds shows her boyfriend bleeding from gunshot wounds while an officer points a gun through the window of their car.

Reynolds's four-year-old daughter is in the backseat while Philando Castile sits drenched in his blood.

The video was temporarily removed for nearly an hour and reactivated with a warning about its graphic content. A Facebook spokesperson told TechCrunch it was "due to a technical glitch."

Millions of people have now viewed the video and many turned to Twitter to express their outrage. Users latched onto the #SayHisName hashtag to call attention to the number of black men dying at the hands of police.

The #SayHisName and #SayHerName hashtags first emerged after singer Janelle Monae and Wondaland Records released a protest song titled Hell You Talmbout in August of last year.

In the song, they chant the names of black citizens killed by police, including Michael Brown, Aiyana Jones, Eric Garner and others. The artists sing, "Walter Scott, say his name / Walter Scott, won't you say his name?"

The release coincided with Monae and her Wondaland artists leading a Black Lives Matter protest in Philadelphia.

Many Twitter users found themselves at a loss for words after witnessing these consecutive tragedies, tweeting their emotional reactions.

Reynolds says Castile told the officer, who pulled him over for a broken taillight, that he had a gun in the car and a licence for it. Carrying a weapon is legal in Minnesota if you have a permit.

Some Twitter users say the National Rifle Association's silence on the shooting is a result of the group's inherent racism.

The videos are evidence that social networks and live streaming can play a significant role in calling attention to injustices, but things don't seem to change.

Roxane Gay, author and an associate professor at Purdue University, wrote an op-ed for the New York Times describing the frustration.

"I don't think any of us could have imagined how tiny cameras would allow us to see, time and again, injustices perpetrated, mostly against black people, by police officers," Gay writes. "I don't think we could have imagined that video of police brutality would not translate into justice, and I don't think we could have imagined how easy it is to see too much, to become numb. And now, here we are."

"It is a bitter reality that there will always be a new name to that list. Black lives matter, and then in an instant, they don't."