The Islamic State on Tuesday released a video showing the beheading of American journalist James Foley. Foley was an experienced reporter who covered numerous conflicts, with samples of his work here.

United States security officials believe the Islamic State video purporting to show the beheading of American journalist James Foley is authentic.

"The U.S. Intelligence Community has analyzed the recently released video showing U.S. citizens James Foley and Steven Sotloff," National Security Council spokeswoman Caitlin Hayden said. "We have reached the judgment that this video is authentic. We will continue to provide updates as they are available."

"The FBI on Wednesday morning told the Foley family they believe the video is authentic," according to GlobalPost, the Boston-based online publication that employed Foley as a freelancer when he disappeared in Syria in 2012.

U.S. authorities had previously said they were trying to verify the contents of the video, which was released on Tuesday.

Foley's mother said Tuesday her son gave his life to expose the suffering of the Syrian people and she asked his kidnappers to release their other captives.

"He was an extraordinary son, brother, journalist and person," Diane Foley said in a post on a Facebook page set up by the Foley family.

The Islamic State militant group claimed Tuesday to have beheaded the photojournalist in retaliation for U.S. airstrikes in Iraq. Foley was a graduate of Northwestern University’s Medill School of Journalism.

"We implore the kidnappers to spare the lives of the remaining hostages. Like Jim, they are innocents. They have no control over American government policy in Iraq, Syria or anywhere in the world," Diane Foley said in the statement.

Northwestern released a statement saying the "Medill family is shocked and deeply saddened by the news of the murder of James Foley."

"Journalists face threats in many forms as they try to report difficult stories that need to be told, but the attack on Jim was barbaric," Northwestern said in a statement. "It was, in a larger sense, an attack on freedoms necessary in a civilized society and across strained cultures. Jim endures for us as a beacon reminding us of the risks implicit in shedding light where inhumanity can take hold."

A chilling video posted on YouTube, later removed, purported to show the execution of James Foley after he recited a statement in which he called the U.S. government “my real killers.”

“I call on my friends, family and loved ones to rise up against my real killers — the U.S. government. For what will happen to me is only a result of their complacent criminality,” the kneeling man says.

A second prisoner, said to be Steven Sotloff, like Foley an American journalist who disappeared while covering Syria’s civil war, then appears in the video.

The black-clad, masked executioner, speaking in English with an apparent British accent, identifies Sotloff and says that “the life of this American citizen, Obama, depends on your next decision.”

Both prisoners in the video are wearing orange shirts and pants, similar to orange jumpsuits worn by detainees at the U.S. military prison at Guantanamo Bay, Cuba. A similar outfit, believed to be a jihadist symbol of the prison, was worn by Nicholas Berg, an American businessman kidnapped in Iraq in 2004 whose execution by an Islamic State precursor organization was videotaped and posted online.

Foley, 40, who received a master’s degree from Medill in 2008, was working in Syria for GlobalPost when he disappeared on Thanksgiving Day, 2012.

While attending Medill, Foley worked as a language arts teacher at the Cook County Sheriff’s boot camp program for four or five years, said Cara Smith, executive director of the Cook County Jail.

“He was a passionate and dedicated teacher in our boot camp,” Smith said. The program is an alternative to a state prison sentence.

“He was fluent in Spanish and was able to connect with our Spanish-speaking boot camp participants,” Smith said. “He believed passionately in education and its ability to reduce recidivism.”

Foley, a native of New Hampshire, reported about conflicts in Iraq, Afghanistan, and Libya, where he was held captive for 44 days.

After his release in Libya in 2011, Foley returned to Medill for an event in which he was interviewed by Tim McNulty, a Medill lecturer and former Chicago Tribune associate managing editor. Foley emphasized the importance of informing Americans about conflicts overseas.

“'Conflict journalism' is very important. ... We need to know that most of the world is a dictatorship,” Foley said. “Most of the world, you cannot speak your mind. Most of the world, there’s no due process. Being away from the U.S. for a long time in these places, it really got knocked into me this time, man. We live in a pretty good place.”