An online image circulated Wednesday purported to show the beheading of a Croatian hostage held by the Islamic State group’s Egyptian affiliate, the first such killing of a foreign captive in Egypt since the extremists set up a branch here.

The killing of the 30-year-old oil and gas sector surveyor likely will rattle companies with expatriate workers in Egypt and cast a cloud over President Abdel-Fattah el-Sissi’s attempts to boost international investment to revive the economy, battered by years of turmoil.

The still image, shared by Islamic State sympathizers on social media, showed the apparent body of Tomislav Salopek, a married, father of two, wearing a beige jumpsuit looking like the one he had worn in a previous video. A black flag used by the Islamic State group 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.

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. Croatian troops also were part of the coalition forces in Iraq and they still serve in the NATO-led force in Afghanistan.

Egyptian Foreign Ministry officials were not immediately available for comment. An official at the Croatian Embassy in Cairo who refused to give his name said the embassy cannot comment on the incident. The Croatian Foreign Ministry declined to immediately comment.

The Associated Press could not independently verify the image. However, it bore markings consistent the filmed hostage demand the group made last week.

In that video, the Islamic State affiliate set an Aug. 7 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 the country’s Islamist president.

The extremists’ videotaped demand was entitled “A Message to the Egyptian Government,” and was shot in the style of previous Islamic State propaganda videos.

Salopek, a surveyor working with France’s CGG Ardiseis, was abducted in western Cairo last month. The company has an office in the leafy Maadi suburb, where many expats and diplomats live.

Last week, Croatian Foreign Minister Vesna Pusic met with her Egyptian counterpart in Cairo to press for Salopek’s release, while Egyptian Foreign Minister Sameh Shoukry’s office pledged in statement that Egypt would ” spare no effort” in the search for him.

The Islamic State group holds about a third of Iraq and neighboring Syria in its self-declared “caliphate.” In Syria, Islamic State 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.

In Libya, an Islamic State affiliate also has beheaded its captives. In February, they released a video showing them behead a group of Coptic Christians from Egypt in an online video. In April, another video showed them behead and shoot dead groups of Ethiopian Christians.

Egypt has seen an increase in violence since the ouster of Islamist President Mohammed Morsi, with attacks by suspected Islamic extremists in both the Sinai Peninsula and the mainland focusing primarily on security forces.

Foreign interests also have been targeted increasingly, including the Italian Consulate, which was hit with a car bomb last month. That came just days after another bomb killed Prosecutor General Hisham Barakat in an upscale Cairo neighborhood.

But this is the first time the local Islamic State affiliate purportedly has killed a captive foreigner in Egypt, a major escalation as the country tries to rebuild its crucial tourism industry after years of unrest following the 2011 revolt against autocrat Hosni Mubarak.

Last December, the affiliate claimed responsibility for the killing of an American oil worker with Texas-based energy company Apache Corp. Apache had said that previous August that one of its supervisors had been killed in an apparent carjacking in the Western Desert, part of Egypt’s mainland.

(AP)