ISIS has threatened Twitter founder Jack Dorsey and his employees after the site removed accounts linked to the extremists . Twitter confirmed to Daily Mail Online that the company was working with authorities to verify the seriousness of the threat which claimed employees ' necks are ' a target for the soldiers of the Caliphate ' . The chilling warning , written in Arabic , featured a picture of Dorsey in a gun 's cross-hairs and the Twitter logo . It was posted on Sunday on an anonymous site based in Poland which is used by programmers to share code . Dorsey , who is worth an estimated $ 2.5billion and lives in California , made no mention of the threat online on Sunday as he tweeted his 2.87million followers . The threat featured a picture of Twitter billionaire co-founder Jack Dorsey in a gun 's cross-hairs and the Twitter logo . The alleged threat , first reported by Buzzfeed , mentioned Dorsey and included the words : 'We always come back . ' In a statement to Daily Mail Online , a Twitter spokesperson said on Monday : 'Our security team is investigating the veracity of these threats with relevant law enforcement officials . ' When entered into Google translate ( which does not provide an exact translation ) the message is titled : 'Tweets in response to a campaign to delete accounts . ' It goes on : 'You started this failed war ' . The message then appears to address Dorsey directly and Twitter employees . It reads : 'Hey Jack ... when their necks officially become a target for the soldiers of the Caliphate and supporters scattered among your midst ! ' It also claimed killing employees 'outside a neighborhood pub ' would be no more preventable than the massacres of Charlie Hebdo killer Amedy Coulibaly and Copenhagen shooter Omar el-Hussein . The message later reads : 'Imagine the scene and wait for its occurrence at any moment , and the earliest opportunity ! 'Virtual your war on us in the Internet will pull you real wars on earth ! ' It closes with the threat : 'Is the message reached my Twitter ? ' ISIS have posted horrific videos and images of executions , including beheadings , on mainstream sites online . According to Twitter 's rules : 'You may not publish or post direct , specific threats of violence against others . ' Twitter and YouTube both removed violent material and propaganda linked to ISIS . California-based Dorsey made no mention of the Twitter threat as he tweeted his 2.87million followers on Sunday night . Killers : The message compared its threat to the murders carried out in Paris by Amedy Coulibaly ( left ) and in Copenhagen by Omar el-Hussein ( right ) . So-called 'lone wolf ' attackers are encouraged by online messages .
Twitter confirmed to Daily Mail Online on Sunday that the company was working with authorities to verify the seriousness of the threat . The threat , featuring a picture of Dorsey in a gun 's cross-hairs and the Twitter logo , was posted on Monday .