NICE, France—A brazen young career criminal was wounded but escaped during a firefight with police after a shooting and stabbing rampage in Strasbourg’s storied Christmas market Tuesday night.

French authorities declared it a terrorist attack, briefly locked down the city, and launched a massive manhunt. Two people were killed, one was left brain-dead and at least eight were critically injured in the murder spree that came out of nowhere around 7:50 p.m. as a man dressed all in black and armed with a knife and a pistol began shooting and then stabbing Christmas shoppers.

Paris Prosecutor Rémy Heitz, whose office leads terrorism investigations across the country, said witnesses reported that the suspect yelled “Allahu Akbar” during the attack.

And suddenly, dramatically, almost totally, the thousands of protesters wearing yellow automobile safety vests who have dominated the news in France and out of France for the last month suddenly discovered they were no longer in the spotlight.

They had never been there before, and maybe they thought they would be there forever, standing around barricades being interviewed on camera or trashing French cities amid clouds of tear gas. But by Wednesday afternoon the amorphous ad hoc social media-based movement’s self-proclaimed voices were going unheard.

What had been wall-to-wall coverage of France’s sometimes violent Yellow Vest movement was suddenly and totally eclipsed by nonstop coverage of the Strasbourg attack.

They didn’t like it, and just minutes after the Tuesday night attack, some members of France’s Yellow Vest protest group inundated social media with conspiracy theories suggesting French officials staged the Strasbourg carnage. They accused President Emmanuel Macron and his government of plotting to divert attention away from the now three-and-a-half-week-long protest.

Local authorities in Strasbourg reacted almost as quickly, warning in a tweet Tuesday night against spreading “false rumors.”

By Wednesday the conspiracy theorists were splitting apart the already heterogeneous, often inchoate movement, with some gilets jaunes temporarily shutting down Facebook pages because of videos and comments made by their own comrades.

Some wondered if the group’s so-called “Act V” protest planned for Saturday in Paris and provincial cities would even take place—or be considerably muted out of respect for those killed and injured in the attack.

“This has nothing to do with us,” a Yellow Vest on the Place Masséna in Nice who gave only her first name, Marie, said Wednesday. “It is sad but it can’t stop us.”

Actually, it might.

Some speculated that Macron would use the tragedy to shame the Yellow Vests into abandoning their upcoming protests or enact emergency measures that would make them impossible to carry out. Indeed, government ministers have since asked the protesters to call off their protests this Saturday, saying that dealing with the terror attack should be the highest priority. But their problem may be less with the government than with public attention and sympathy.

Maxime Nicolle, a.k.a. “Fly Rider,” one of the most mediagenic and controversial leaders of the Yellow Vests, released a Facebook Live video on the 135,000-member “Fly Rider Infos Blocage” page after the attack pointing out what he claimed were obvious holes in the official story.

“Do you really think that a guy who wanted to carry out a terror attack would wait until there were three people in the street at 8 p.m.?” Nicolle asked his viewers, which have numbered in the hundreds of thousands. “He would go in the middle of the Champs-Élysées and blow himself up.”

Nicolle’s video appeared to have been yanked from the site early Wednesday morning with a message from one of the page administrators that the page would be “blocked” all day. “COMPLOTISTES!” screamed one commenter denouncing the move. “Conspirators!”

The page turned out not to be blocked on Wednesday after all. Around noon, Nicolle surfaced in another video in which he appeared uncharacteristically contrite, spoke sympathetically about the Strasbourg victims and their families and insisted he had “never called for hate.”

His original video can be seen on the Conspiracy Watch Facebook page.

A movement created on social media soon faced the possibility social media would destroy it.

Other Facebook pages devoted to the Yellow Vest crusade did temporarily shut down. “I hope you understand,” wrote one page administrator Tuesday night. “Too many of the posts are degenerating and out of respect for the Strasbourg victims let’s remain wise and unified.”

AFP journalist Guillaume Daudin used his Twitter account to mock the conspiracy theories and debunk one widely circulated rumor that an image on BFMTV, a French all-news channel, appeared to show the Bas-Rhin prefecture in Strasbourg warning locals about the attack before it happened – as if the government had planned it.

AFP’s fact-checking team tweeted that the image came from an Internet user in a different time zone, making it seem to be hours earlier. BFMTV’s Julien Mielcarek appeared several times on the air Wednesday to also call out the conspiracy theorists and break down inaccuracies in their accusations.

French Education Minister Jean-Michel Blanquer called the conspiracy theories circulated by certain factions of the Yellow Vests “despicable” and an increasingly typical and “negative” reaction by some factions of society.

Meanwhile the Strasbourg shooter was still at large.

He fled the scene after commandeering a taxi and ordering the driver to drop him off near where he lived in the Neudorf area of the city. He hasn’t been seen since but his parents and two brothers reportedly have been taken into custody.

“Where is the killer hiding?” blared the headlines on French television as the search for the suspect who was on the country’s notorious watchlist, the S-files, widened to both sides of the border in France and Germany.

Prosecutor Heitz said the gunman, a 29-year-old Frenchman of Algerian descent and a delinquent since age 10, had been radicalized while serving time in French and German prisons. He had 27 prior convictions in France, Germany and Switzerland and had been released from his last stint in prison in 2015.

French media named him as Chérif Chekatt and police said they identified him via a bizarre turn of events that began Tuesday morning.

According to Heitz, police had gone to his home earlier that day to arrest him in connection with an attempted murder but he was not home. Among other things, they found at least one hand grenade in his apartment.

Dots connected after the attack when the taxi driver notified police about what had happened after dropping the suspect off. He described the man as having a handgun and knife and being wounded in the hand. He added crucial information: the shooter had said the suspect mentioned that police had searched his home that morning and found a grenade.

Thus within minutes of the attacks, the police knew exactly who they were looking for.

Although Chekatt was on the country’s threat watchlist, the suspect was not believed to be a potential terrorist, according to French Deputy Interior Minister Laurent Nunez.