As Twitter users searched for news about today’s shooting at YouTube headquarters, hackers were actively compromising a verified employee account to spread misinformation. In the midst of the attack, an unknown hoaxer hijacked a verified Twitter account belonging to Vadim Lavrusik, a product manager at YouTube, and used the high-profile account to implicate a YouTube broadcaster in the shooting.

The account hijacking seems to have taken place while Lavrusik and his colleagues were still near the scene of the attack. Lavrusik reported himself safe at 2:36PM PT, and the hoax tweets began posting just 20 minutes later.

“PLEASE HELP ME FIND MY FRIEND I LOST HIM IN THE SHOOTING,” one fake tweet read, linking to a picture of Keemstar, a popular YouTuber, which was posted to Flipboard. Keemstar is not believed to have been involved in the shooting.

We’re on it — jack (@jack) April 3, 2018

The hack was flagged by multiple reporters, and Twitter removed the hoax tweets shortly afterward. CEO Jack Dorsey personally responded that the platform would handle the situation. Even after Twitter executives became aware of the compromise, hoax tweets were still being regularly posted to Lavrusik’s account, only to be instantly deleted. It’s still unclear how the account was first compromised.

Twitter has struggled with misinformation around breaking news events in the past, and a number of other YouTube celebrities have already been erroneously reported as involved in today’s shooting.