Story highlights ISIS releases a video showing the beheading of a man it says was a Russian spy

The captive's killer tells Russians, " We will kill your sons ... for each son you killed here"

(CNN) ISIS released video Wednesday showing the beheading of a man it claims joined the terrorist group but was in fact a Russian spy, as well as a message chastising Russian President Vladimir Putin and threatening his country's citizens.

As the captive kneels before him in an orange jumpsuit, his killer says in Russian that the airstrikes ordered by Putin against the Islamist extremist group has "made us understand that we are doing right thing" by continuing their fight.

He then addresses the Russian people, saying, "You will not find peace in your homes. We will kill your sons ... for each son you killed here. And we will destroy your homes for each home you destroyed here."

Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims The first U.S. citizen to be killed by ISIS, James Foley was taken hostage in Syria in November 2012 and beheaded in August 2014. The 40-year old from Rochester, New Hampshire was an experienced war journalist who contributed videos to major media outlets including Agence France-Presse and GlobalPost. Hide Caption 1 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Also a freelance journalist, Steven Sotloff disappeared during a reporting trip in Syria in August 2013 and was beheaded a year later. The U.S.-Israeli citizen, who wrote for publications like Time, Foreign Policy and Christian Science Monitor, was when he died. Hide Caption 2 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims British national David Haines was abducted in March 2013 while working at a Syrian refugee camp for an aid group and executed a year later. The 44-year-old father of two had more than a decade of experience doing aid work providing logistics to Handicap International and as an unarmed peacekeeper with Nonviolent Peaceforce. Hide Caption 3 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Originally a taxi driver from the UK, Alan Henning was volunteering to deliver food and water to people affected by the Syrian civil war. He traveled to the Middle East in December 2013, was taken hostage on Boxing Day and held for more than a year before being killed. Hide Caption 4 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Peter Kassig , who served briefly as a U.S. Army Ranger, was working as a humanitarian worker in Syria when he was kidnapped on October 1, 2013 en route to deliver food and medical supplies. The 26-year old was confirmed dead after ISIS posted a video on November 16, 2014. Hide Caption 5 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Haruna Yukawa was a 42-year-old Japanese national who aspired to become a security contractor to Japanese companies in conflict zones. He was in the hands of ISIS for several months before a video released in January showed his killing. Hide Caption 6 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims A freelance journalist, 47-year-old Kenji Goto worked in Syria and other war-torn countries for numerous outlets including Japan's public broadcaster NHK. Goto was in Japan when news surfaced about the capture of Haruna Yukawa, who he had befriended while working in the region. Goto returned to Syria hoping to negotiate his release but was himself captured and later executed. Hide Caption 7 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Royal Jordanian Air Force pilot Moath al-Kasasbeh went missing when his plane crashed during a December 2014 mission. A devout Muslim who memorized the Quran, the 27-year old was shown in an ISIS video in February where he was brutally burned alive. Hide Caption 8 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Kayla Mueller, was a 26-year-old humanitarian worker from Prescott, Arizona, who was taken hostage in August 2013 in Syria. Although the circumstances of her death are unclear, it was confirmed in February when ISIS sent a private message to her family. U.S. government officials later revealed that she had been tortured and sexually abused by ISIS' top leader Abu Bakr al Baghdadi during her captivity. Hide Caption 9 of 10 Photos: Aid workers, journalists, pilots -- a look at ISIS' high profile hostage victims Croatian national Tomislav Salopek was a topographer who was kidnapped in July while driving to work in Egypt, the Croatian foreign ministry said. In August, ISIS released a video showing his apparent beheading. The same month the group posted another video, showing the decapitated head and body of antiquities expert Khaled al-Asaad . The 82-year old, who dedicated his life to preserving cultural relics, was killed for not revealing the location of ancient treasures. Hide Caption 10 of 10

CNN could not immediately verify the authenticity of the video, much less the ISIS claim that the man beheaded was a Russian spy. CNN also was unable to immediately obtain a comment from the Russian government about whether it believes the video shows a Russian citizen being killed.

But if the video is authentic, it joins a growing catalog of atrocities in which the terror group has broadcast the killing of one or more captives and paired it with menacing messages.

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