Twitter employees, co-founder threatened by IS

WASHINGTON, March 2 (UPI) -- Twitter is investigating alleged death threats by the Islamic State on the company's co-founder Jack Dorsey and its employees.

Law enforcement officials are working with the company to determine if the threats are legitimate.

The threat was first posted on JustPaste.it, an anonymous "pastebin" website commonly used by programmers to store and share pieces of computer code.

Jack Dorsey was threatened directly and the message condemned Twitter for shutting down some 2,000 Islamic State-related accounts.

A source with knowledge of Twitter's recent campaign to shut down the accounts told ABC News the social media company was not under pressure from the U.S. government to do so. In fact, the source said, intelligence workers would prefer the IS accounts remain open in order to keep an eye on the terror group's activities.

Top U.S. security officials previously said ISIS has successfully leveraged social media networks, including Twitter, as powerful recruitment tools to draw in fighters from 90 countries. But a person with knowledge of Twitter's recent suspension spree said it was not done due to U.S. government pressure -– in fact, he said the U.S. intelligence community would prefer the accounts stay open for intelligence gathering purposes.

"You started this failed war. We told you from the beginning it's not your war, but you didn't get it and kept closing our accounts on Twitter, but we always come back," a post directed at the company said. "For the 'individual jihadi' all over the world, target the company and its interests in any place, people, and buildings, and don't allow any one of the atheists to survive."

Twitter said in a statement following the threats that it is carefully looking into the matter.

"Our security team is investigating the veracity of these threats with relevant law enforcement officials," Twitter told CNBC in a statement.