An online image circulated on Wednesday purported to show a Croatian hostage held by the Islamic State (IS) group's Egyptian affiliate, Sinai Province, having been beheaded.
The still image, shared by IS sympathizers on social media, showed the apparent body of Tomislav Salopek, a married, 30-year-old father of two, wearing a beige jumpsuit looking like the one he had worn in a previous video. A black flag used by IS and a knife were planted in the sand next to him.
The photo carried a caption in Arabic that said Salopek was killed "for his country's participation in the war against the Islamic State," and after a deadline had passed for the Egyptian government to meet their demands.
A spokesman from the Egyptian Interior Ministry's press office today said: "We have seen this news online but are currently making our own checks. If we confirm that it is indeed true, we will inform the media through a statement."
This comes after the Sinai Province set a Friday deadline for Egyptian authorities to free "Muslim women," a term referring to female Islamist prisoners detained in a sweeping government crackdown following the 2013 military ouster of an Islamist president.
The picture also contained an inset of two Egyptian newspaper reports, with one headline declaring Croatia's support of Egypt in its war against terrorism and extremism, and another saying Croatia reiterated its support for the Kurdistan region.
The IS group holds about a third of Iraq and neighboring Syria in its self-declared "caliphate." In Syria, its militants have killed foreign journalists and aid workers, starting with American journalist James Foley in August last year.
Foley's taped beheading was followed by the killing of American-Israeli journalist Steven Sotloff, British aid workers David Haines and Alan Henning, American aid worker Peter Kassig, as well as Japanese nationals Haruna Yukawa and Kenji Goto.
The Associate Press contributed to this report.