YouTube's top-trending video slot usually goes to songs, movie trailers or funny clips.

Early Wednesday morning, it took a much darker tone, with the No .1 spot held by a video accusing David Hogg, a survivor from last week's deadly high school shooting in Florida, of being a "crisis actor." The trending video on YouTube about Hogg had been viewed more than 200,000 times since it was uploaded 22 hours earlier.

By later Wednesday morning, YouTube had removed the video, which was based on a clip from a CBS Los Angeles broadcast in August 2017. It shows Hogg on California's Redondo Beach, where he filmed an incident between one of his friends and a lifeguard during a family vacation. (Disclosure: CBS is the parent company of CNET.) 

YouTube said the video never should have appeared in "trending."

"Because the video contained footage from an authoritative news source, our system misclassified it, " a YouTube representative said. "As soon as we became aware of the video, we removed it from Trending and from YouTube for violating our policies. We are working to improve our systems moving forward."

Hogg, who is 17, is one of the organizers behind March for Our Lives, a call to action on gun control after a former student opened fire at Marjory Stoneman Douglas High School in Parkland, Florida, on Feb. 14. Since speaking out, Hogg has become the target of conspiracy theories flooding the internet, accusing him of being a "crisis actor," or someone paid to pretend to have been affected by a tragedy for political gain. 

CBS Los Angeles has confirmed that Hogg is an MSD High School student. He is also the son of a former FBI agent. 

"People think that I'm an actor," Hogg told CBS Los Angeles, "but... I don't have time to care about that. I have to keep going." 

He also said he doesn't understand the hate he's suddenly facing.

"I witnessed this event, why are you guys doing this to me? I'm trying to be as well spoken as possible because these politicians won't," he said.

The conspiracy theories have already become so widespread that they cost a Florida state representative's aide his job after he accused the student activists of being actors. 

On Instagram, there are thousands of posts with conspiracy theories and photoshopped memes of Hogg under the hashtag "#crisisactor." On Facebook, more than 100,000 posts are talking about Hogg, and the student activist became a trending topic by Wednesday morning. One of the videos under the trending topics has more than 1 million views and also accuses Hogg of being a crisis actor.

Facebook did not respond to a request for comment.  

Facebook, Google and Twitter have been struggling to squash disinformation and conspiracy theories that spread across their platforms. Twitter had to deal with Russian bots trolling the social network almost immediately after the Florida shooting, and now these conspiracy theories are echoing throughout YouTube, Facebook and Instagram. 

Sen. Marco Rubio, a Republican from Florida, condemned the conspiracy theories on Tuesday, calling them "the work of a disgusting group of idiots." 

Social media companies have vowed to fix disinformation issues, but they continue to pop up.

First published, Feb. 21 at 7:35 a.m. PT.
Update, 8:35 a.m. PT: YouTube has removed the conspiracy theory video about David Hogg.
Update, 9:04 a.m. PT: Added remarks from Sen. Marco Rubio.
Update, 9:45 a.m. PT: Added comment from YouTube.

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