Story highlights Images appears to show hostage Kenji Goto holding a photo of captive Jordanian

Voice, purportedly Goto's, says he, Jordanian pilot will die in 24 hours if swap isn't made

Video repeats demand ISIS apparently made Saturday: Jordan must release prisoner

(CNN) A video file posted online Tuesday purports to relay a new message from Japanese ISIS hostage Kenji Goto: He and a captive Jordanian military pilot will be killed in the next 24 hours if Jordan doesn't release a convicted would-be suicide bomber.

It is the second purported message from Goto in four days. If authentic, it is the first time ISIS is publicly linking the fates of Goto and the captive Jordanian pilot, Moaz al-Kassasbeh, whom ISIS captured after his jet crashed last month in Syria.

The latest file, posted to YouTube and distributed on social media by known ISIS supporters, appears to show a static image of Goto, alone, in handcuffs and wearing orange, holding a picture of who appears to be al-Kassasbeh.

Over the image, a voice purporting to be Goto's restates Saturday's apparent ISIS proposal: Goto would go free if Jordan releases longtime prisoner Sajida al-Rishawi

This time, it's still a one-for-one swap, but now both the lives of Goto and the Jordanian pilot are threatened if it doesn't go through. CNN cannot independently verify the authenticity of Tuesday's message.

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