A video that shows the beheading of American Steven Sotloff was delivered as a `` second message to America '' to halt airstrikes in Iraq , following through on a threat to kill the journalist . In the video posted Tuesday online , Sotloff says -- in a message surely scripted by his captors -- that he is `` paying the price '' for U.S. military intervention . The intelligence community in the United States is working to confirm the authenticity of the video , and the journalist 's family was waiting for that formal authentication that Sotloff has been killed . `` The family knows of the video and is grieving privately , '' family spokesman Barak Barfi said . Who is ISIS ? The killing of Sotloff follows a threat last month by ISIS made during the videotaped beheading of American journalist James Foley . The latest video threatens the life of another man . A masked ISIS figure in the new video speaks to U.S. President Barack Obama , telling him , `` Just as your missiles continue to strike our people , our knife will continue to strike the necks of your people . '' The Islamic State has thrived and mutated during the civil war in Syria . It swept into Iraq in June , seizing large swaths of the country 's Sunni-dominated northern and western provinces . Obama ordered targeted airstrikes in Iraq to begin in early August after ISIS fighters began targeting ethnic Yazidis and launching attacks toward the Kurdish regional capital of Irbil . ISIS appeared to date the execution video of Sotloff , referencing specific U.S. military actions in recent days , including U.S. airstrikes that helped over the weekend to break the siege of Amerli -- a northern Iraqi town home to thousands of minority Shiite Turkmen . Intelligence officials are analyzing the video , trying to answer some key questions , a senior U.S. administration official said . Among the questions , the official said : When was it shot ? Where was it shot ? Is the killer in the Sotloff video the same one in the Foley video ? Until they answer those questions , the official said the administration does not want to speculate . It 's believed ISIS is still holding a `` small number '' of Americans hostage , said the official , who spoke on condition of anonymity . Beheading of American journalist James Foley recalls past horrors . ISIS : 'Back off and leave our people alone ' In the new video , the militant threatens the life of the man , who is shown kneeling with the militant standing behind him . `` We take this opportunity to warn those governments who 've entered this evil alliance of America against the Islamic State to back off and leave our people alone , '' the militant says . CNN could not immediately confirm when he was taken captive . But the Washington Post reported he was an aid worker abducted in March 2013 . The newspaper , citing unnamed aid workers involved in efforts to gain his release , said he was abducted near a refugee camp in the northern Syrian province of Idlib . British Prime Minister David Cameron told reporters he was aware of reports about the video and called Sotloff 's killing `` an absolutely disgusting and despicable act . '' Who was Sotloff ? Sotloff disappeared while reporting from Syria in August 2013 , but his family kept the news secret , fearing harm to him if they went public . Out of public view , the family and government agencies had been trying to gain his release for the past year . Last week , Sotloff 's mother , Shirley Sotloff , released a video pleading with ISIS leader Abu Bakr al-Baghdadi not to kill her son . `` Steven is a journalist who traveled to the Middle East to cover the suffering of Muslims at the hands of tyrants . Steven is a loyal and generous son , brother and grandson , '' she said . `` He is an honorable man and has always tried to help the weak . '' Her plea was met with taunting responses on social media by ISIS supporters . Sotloff , 31 , grew up in South Florida with his mother , father and younger sister . He majored in journalism at the University of Central Florida . His personal Facebook page lists musicians including the Dave Matthews Band , Phish , Miles Davis and movies including `` Lawrence of Arabia '' and `` The Big Lebowski '' as favorites . On his Twitter page , he playfully identifies himself as a `` stand-up philosopher from Miami . '' He graduated from another college , began taking Arabic classes and subsequently picked up freelance writing work for a number of publications , including Time , Foreign Policy , World Affairs and The Christian Science Monitor . His travels took him to Yemen , Saudi Arabia , Qatar and Turkey -- among other countries -- and eventually Syria . Editor Nancy Gibbs said the magazine 's staff is `` shocked and deeply saddened '' by the reports of his death . `` He gave his life so readers would have access to information from some of the most dangerous places in the world , '' she said . `` Our thoughts and prayers are with him and his family . '' Sotloff brings the number of journalists killed in Syria to at least 70 , according to the Committee to Protect Journalists . More than 80 have been kidnapped in Syria since the civil war began , with many going unpublicized , the group said . `` We condemn in the strongest terms possible the murder of journalist Steven Sotloff . He , like James Foley , went to Syria to tell a story . They were civilians , not representatives of any government . Their murders are war crimes and those who committed them must be brought to justice swiftly , '' CPJ said . Obama on ISIS -- No strategy yet . Response from the White House . White House spokesman Josh Earnest said the administration `` has obviously been watching very carefully since this threat against Mr. Sotloff 's life was originally made a few weeks ago . '' A top U.S. State Department official told CNN 's Christiane Amanpour to `` stay tuned '' on U.S. plans to combat the organization . `` We are putting the features in place , developing a broad regional coalition , a broad international coalition , working to get a new Iraqi government stood up , working to get our plans in place . So stay tuned , '' said Brett McGurk , the deputy U.S. assistant secretary of state for Iraq and Iraq . Obama , who was briefed on the videotaped execution of Sotloff , came under fire from Republicans and Democrats who called on the President to take stronger against ISIS , also known as ISIL . The criticism came a week after Obama said , `` We do n't have a strategy yet '' to deal with ISIS in Syria . Obama said he has asked America 's top defense officials to prepare `` a range of options . '' `` Mr. President , if you ca n't come up with a strategy , at least tell us what the goal is regarding ISIL , '' said Sen. Lindsey Graham , R-South Carolina . Sen. Jeanne Shaheen , D-New Hampshire , said ISIS must be stopped . `` We must use every tool at our disposal , short of introducing ground forces in combat roles , to put an end to the threat they pose to our national security , '' she said . Opinion : Foley is a reminder why freelance reporting is so dangerous .
`` Stay tuned '' for plans to combat ISIS , a State Department official says . A video has emerged showing the 31-year-old journalist being beheaded . Footage threatens the life of another man . The U.S. is working with Turkey and Saudi Arabia on an operation against Islamic militants in Iraq and Syria.