IS beheads US journalist
This screenshot from a video uploaded by the Islamic State show US photojournalist James Foley with his executionerScreenshot of the IS video taken from SITE Intelligence

Global Post, the news organization where slain US journalist James Foley worked, has released the full text of a letter sent to the scribe's family members by his Islamist militant captors, in which the jihadists have clearly stated their intention to execute Foley in retaliation to US airstrikes.

Boston-based online news publication GlobalPost said on Thursday that Foley's family had agreed to release the email that they had received a week before the IS militants released the video showing his execution. The publication added that it has chosen to "publish it in full in the interest of transparency and to fully tell Jim's story."

"We believe the text offers insight into the motivations and tactics of the Islamic State," the publication said.

The email itself, not only espouses extreme views of the militants, but threatens to do everything they can to prevent Americans from killing their citizens while calling the US citizens they have captured as the "the scum of your society who are held prisoner by us."

"THEY DARED TO ENTER THE LION'S DEN AND WHERE EATEN!" the heavily worded letter states.

"You were given many chances to negotiate the release of your people via cash transactions as other government have accepted," it further says. "We have also offered prisoner exchanges to free the Muslims currently in your detention...however you proved very quickly to us that this is NOT what you are interested in."

The chilling letter addressed as "a message to the American government and their sheep like citizens" argues that the Obama administration has now returned "to bomb the Muslims of Iraq once again, this time resorting to Arial attacks and 'proxy armies', all the while cowardly shying away from a face-to-face confrontation!"

Asserting that the United States did not spare their women, children or elderly, the jihadists vowed that they would do exactly the same.

"Today our swords are unsheathed towards you, government and citizens alike!" it warns.

"AND WE WILL NOT STOP UNTIL WE QUENCH OUR THIRST FOR YOUR BLOOD."

The email ends with a declaration that Foley "will be executed as a DIRECT result of your transgressions towards us!"

The news organization, however highlights that there were many inaccuracies in the email such as the fact that the Foley family "was not 'given many chances to negotiate' for Jim's release".

"After more than a year without contact, the Foleys received their first message from Jim's captors on November 26, 2013, asking for money, fast," the publication added. "After the militants had proved to the Foleys and investigators that they were in fact holding Jim, they made their sole demand for a ransom of €100 million (about $132 million) or the release of unspecified prisoners held by the United States," it said.

The Foleys heard back from them only via this threatening email this month, GlobalPost said.