Less than an hour after tweeting about being safe during an active shooting at YouTube's headquarters, Vadim Lavrusik's account was hit by hackers. 

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Lavrusik, a product manager at YouTube, sent one of the first tweets out about an active shooting at the office in San Bruno, Calif., at 12:57 p.m PT. The first 911 call for the shooting had come in at 12:46 p.m. PT, and police arrived in two minutes, San Bruno Police Chief Ed Barberini said at a press conference on Tuesday. 

At about 2:10 p.m., after Lavrusik tweeted that he was safe and evacuated, a new tweet came up from the account, writing, "PLEASE HELP ME FIND MY FRIEND I LOST HIM IN THE SHOOTING," with a Flipboard URL linking to a photo of KEEMSTAR, a YouTube personality. 

Three minutes after that tweet, another post came in saying, "my name is so gay honestly." 

The tweets were quickly deleted and there have been no new tweets from Lavrusik's account since, but "see new tweets" continued to pop up on the account, and disappear when clicked. Flipboard didn't respond to a request for comment. 

Twitter's CEO Jack Dorsey responded to the concerns, tweeting that the social network was working to fix the issue. 

Asked for comment, Twitter referred us to a tweet it posted stating: "We are also aware of attempts by some people to deceive others with misinformation around this tragedy. We are tracking this and are taking action on anything that violates our rules."

Lavrusik tweeted at 4:35 p.m. PT that his account had been restored and thanked Dorsey.

The shooting has left three people injured, and the suspected shooter dead, according to police. A 32-year-old woman, a 27-year-old woman and a 36-year-old man were transported to the Zuckerberg San Francisco General Hospital, with gunshot wounds. 

First published April 3 at 3:32 p.m. PT.
Update at 3:45 p.m.: Adds comment from Twitter.
Update at 3:37 p.m.: Changes the number of injured per new information.
Update at 4:57 p.m.: Adds Lavrusik's account has been restored.