DeRay McKesson live-streamed his arrest during a Black Lives Matter protest in Baton Rouge

DeRay McKesson, one of the most recognizable faces of the mostly leaderless Black Lives Matter movement, was arrested on Saturday night in Baton Rouge, Louisiana, where he had joined protests against the shooting by white police officers of Alton Sterling, a black man.

McKesson, a public school administrator, recorded his own arrest live on Periscope. He was filming as protesters marched up Airline Highway at about 11.15 pm. The video shows lines of flickering police lights in the distance. McKesson realizes that police are arresting protesters and stops to record video of the interactions. Then one officer points at McKesson and approaches him.

“You with them loud shoes,” an officer says. “I see you in the road. If I get close to you, you’re going to jail.”

McKesson’s trademark clothing is red shoes, a red hat and a blue vest (he wasn’t wearing the vest when he was arrested.) One of the other protesters says “you’ve been flagged.” McKesson explains on the video that there is no sidewalk on the highway where they’re marching, and points the camera down to show that they’re keeping within the painted line on the side of the road.

Related: Emails Show Feds Have Monitored ‘Professional Protester’ DeRay Mckesson

An officer comes up from behind McKesson and says “City Police. You’re under arrest, don’t fight me.”

“What?” McKesson says, surprised. “I’m under arrest, y’all.”

The feed goes dark and the phone apparently drops. Moments later, it starts up again.

Fellow activist Brittany Packnett takes over the live feed on Periscope and shows McKesson being led away by officers. She tells viewers that McKesson was singled out in a group of 15 or so people. A man and a woman shout “Why are you arresting him? He didn’t do anything.” Someone asks, “Where’s Netta?” – referring to Johnetta Elzie, who is one of the other prominent faces of the BLM movement. One woman starts crying.

Packnett wrote in an email to VICE News that “multiple police” tackled McKesson. “To our knowledge there were over 100 protesters arrested including a teenager trying to pick up [McKesson’s] phone and a journalist,” Packnett wrote. An NPR reporter and a local broadcaster were both arrested. ABC News reported 101 arrests overnight related to the protests. Baton Rouge Police Department’s office of public information was not answering phone calls.

“During this time, the Police have continually been the aggressors in peaceful protest,” Packnett wrote. “They intentionally provoked peaceful people, pushing them from lawful spaces with riot shields and pointing guns in faces.”

A reporter on the scene from The Advocate asked a police officer if those accusations were true.

Here’s @LAStatePolice Maj. Cain answering Qs about why cops apparently rushing crowd unprovoked #altonSterling pic.twitter.com/9n4Ix89Zj8
— Maya Lau (@mayalau) July 10, 2016

Louisiana recently enacted a “Blue Lives Matter” bill, becoming the first state to make law enforcement a protected class under hate-crime law. The slogan “Blue Lives Matter” is rooted in the notion that the “Black Lives Matter” movement advocates violence against individual police officers, which the movement does not, in fact, do.

Related: Attacking a cop in Louisiana will be a hate crime if gov. signs ‘Blue Lives Matter’ bill

McKesson and others were protesting the death of Alton Sterling, who was selling CDs outside a convenience store, his usual spot, when he was tackled to the ground by police officers and shot repeatedly at close range.

The final moments of his life and his death were captured on a grainy cellphone video.

The country had barely recovered from Sterling’s shocking death when, days later, another black man was killed by police, this time in Minnesota.

Related: What we know about Baton Rouge police shootings before Alton Sterling

Philando Castile was shot by a police officer in broad daylight during a routine traffic stop. His girlfriend, who broadcast the aftermath live on Facebook, and her daughter were in the car at the time.

Protests in Minnesota over Castile’s death became heated on Saturday night. Footage and photos emerging from the scene showed riot police clashing with protesters who shut down a major highway for hours, in a shift from the mostly peaceful demonstrations in the area since Castile’s death.

Flashbangs and smoke being used on protesters.#PhilandoCastile #94shutdown pic.twitter.com/8Qkry3on2q
— Nick Espinosa (@CGoHome) July 10, 2016

About 50 to 100 protesters were arrested.

At least five police officers were reportedly injured by rocks, fireworks, bricks and glass bottles that were thrown by protesters, none seriously.

Protesters also shut down traffic in New York City, Miami and Chicago on Saturday night.