Yesterday afternoon, Donald Trump Jr. posted a graphic video to X (formerly Twitter) that purported to show Hamas fighters murdering Israeli citizens during the attack last Saturday morning. “You don’t negotiate with this,” Trump Jr. wrote. “There’s only one way to handle this.” The son of former US president Donald Trump added that the video had come from a “source within Israel.”

The post was shared widely, and within hours it had amassed over 4 million views.

Then X’s user-generated fact-checking system, Community Notes, appended a message to the tweet, stating: “This is an old video and is not from Israel,” accompanied by a link to the original video. The note suggested that Trump Jr. was contributing to what has been a flood of disinformation on X since Hamas militants attacked Israel on Saturday, supercharged by verified users and accompanied by other conspiracy theories pushed by the company’s owner, Elon Musk.

But WIRED has now verified that the Community Notes system appears to be wrong. According to an independent OSINT analysis published on Wednesday, the video Trump Jr. posted is real. It was recorded during Saturday’s attack and does show Hamas fighters shooting Israelis, the analysis found.

The incident highlights how Community Notes, touted this week by X as one of the crucial ways it was tackling disinformation, is still struggling to function as intended and is, in some instances, adding to the level of disinformation on X rather than correcting it.

The Community Notes system is made up of X users who volunteer to fact-check posts on the site. It is X’s primary fact-checking mechanism since Musk eradicated virtually all full-time Trust and Safety staff and part-time moderators who previously did that work.

The volunteers, who must be approved by X to contribute to Community Notes, suggest notes to add to what they believe are misleading posts. Those notes are only displayed publicly once a sufficient number of volunteers have approved them.

Once approved, notes are regarded as “helpful” and posted publicly. This is how X describes what it sees as a “helpful” note: “Enough contributors from different perspectives agreed that this note is helpful, so it’s being shown as context on the post.”

Earlier this week, X praised the Community Notes team for tackling the misinformation that has flooded the platform in the past week and said new accounts are being enrolled “in real time to propose and rate notes.” On Tuesday, an NBC investigation found the system was not functioning as proposed; of the two Israel-Hamas misinformation claims investigated by the outlet, more than a quarter had notes that remained private as they had not been approved by enough volunteers, while roughly two-thirds had no notes at all.

X replaces the names of users who suggest the notes with aliases, making it impossible to see who submits any particular note. In the case of the note on Trump Jr’s account, the note was submitted by a user pseudonymously identified as “Mellow Sun Swan” four hours after Trump Jr posted the video.

This was the eighth note the user had submitted, according to their profile, but the first to have been approved. The user has in recent days submitted multiple notes on posts related to Iranian links to the conflict.

In the case of the Trump Jr. video, the Community Notes user linked to a video posted on the Iranian social media platform Wisgoon as evidence that the video was from years ago, not this past weekend. In the post, the upload date on the video is in Persian, which, when translated, reads “15 Mehr 1402,” a date in the Persian calendar. This date translates in the Gregorian calendar to October 7, 2023—the date Hamas attacked Israel.

An open source intelligence researcher tells WIRED that they confirmed the video’s veracity by tracking the original video, which was broadcast by a Gaza civilian on a Facebook livestream on Saturday morning. The researcher, who posts anonymously on social media using the handle OSINTtechnical, is frequently cited by news outlets covering conflict zones.

Soon after the Trump Jr. note was published, an account associated with the far right that has advocated for banning the Anti-Defamation League tried to back up the claim about the video being fake, sharing a screenshot that showed the results of a reverse-image search for the thumbnail image of the original video. The results appear to show a series of links to Wisgoon featuring the same image, all of which have dates from seven or eight years ago. However, this is because the recent video was listed in the related videos list of the older videos, not proof that it is an older video.

On Wednesday afternoon, the note on Trump’s tweet was updated to link to the tweet from the account linked to the far right.

X replied with an automated response to WIRED’s questions, stating: “Busy now, please check back later.” Trump Jr. did not respond to WIRED’s request for comment.