WASHINGTON (CNN) -

An outrageous ransom demand. A failed rescue attempt. A taunting e-mail.

These were the details emerging about the final months of the life of American journalist James Foley, whose execution at the hands of Islamic extremists was captured on video and posted online this week as a warning to the United States.

Foley's captors demanded 100 million euros ($132.5 million) in exchange for his release, according to an official with GlobalPost, the U.S.-based online publication the freelance journalist was working for at the time of his abduction in Syria in 2012.

GlobalPost "never took the 100 million seriously" because ransoms paid for other hostages being held by ISIS, which refers to itself as the Islamic State, were "dramatically less," Philip Balboni, president and chief executive of the news agency, told CNN.

Balboni said the amounts paid previously for hostages released was between 2 and 4 million euros. "So we thought that something in the range of $5 million was probably the right amount to pay for the ransom," he said.

There was an effort to raise money. But there was never any true negotiation between the news outlet and Foley's captors, Balboni stressed, saying that ISIS simply made demands.

Foley, 40, was last seen on November 22, 2012, in northwest Syria, near the border with Turkey.

E-mail demands

In six e-mails during the time Foley was missing, the captors "never really negotiated their demands," Balboni said. "They stated a demand and it was 100 million (euros) or the release of Muslim prisoners."

No prisoner was ever named in the messages exchanged between GlobalPost and the captors.

Early on in the contact with the captors, there was an attempt to ascertain whether Foley was indeed alive.

The Foley family was allowed to send three questions that were so specific and personal that only Foley would have known the answers. They received the correct responses, Balboni said, letting them know the journalist was alive.

The last time Balboni heard from ISIS about Foley was August 13, he told CNN.

"The captors never messaged a lot. There was a very limited number with a very specific purpose. ... They made demands," Balboni has said.

Some messages were political and some were financial.

Then came the final e-mail message that was sent to Foley's family last week. In it, the captors made no demand and said the journalist would be killed.

"Today our swords are unsheathed toward you, GOVERNMENT AND CITIZENS ALIKE! AND WE WILL NOT STOP UNTILL (sic) WE QUENCH OUR THIRST FOR YOUR BLOOD," read the e-mail, which was posted by the online news agency on Thursday.

It went on to say, "You do not spare our weak, elderly, women or children so we will NOT spare yours! You and your citizens will pay the price of your bombings! The first of which being the blood of the American citizen, James Foley! He will be executed as a DIRECT result of your transgressions towards us!"

Foley's family, according to Balboni, responded in an e-mail, pleading for mercy and asking for more time.

They did not hear back.

Rescue attempt

The video of Foley's execution was posted online on Tuesday. In it, the executioner, dressed in black, with his face covered, warned the life of another American journalist -- believed to be Steven Sotloff -- hangs in the balance.

The militant in the video, who speaks English with what sounds like a British accent, said the fate of the journalist depends on whether the United States ends its military operations in Iraq.

The threat has done little to curb U.S. military operations in Iraq.

Thursday, American warplanes continued airstrikes against ISIS targets near Mosul Dam, which had been in control of ISIS but was recently reclaimed by Kurdish forces. The United States launched six more airstrikes near the dam in support of Iraqi Security Force operations, according to the U.S. Department of Defense.