A Croatian hostage the Islamic State group claims to have beheaded is thought to have been kidnapped by a criminal gang in Egypt before being turned over to the jihadists, Croatia's foreign minister says.
Tomislav Salopek, a 31-year-old father of two working for a French engineering company, was seized last month from a car some 22km west of Cairo.
One group "believed to be bandits" initially abducted him and then demanded a ransom from his French employer, geoscience group CGG, eight days after the July 22 kidnapping, Foreign Minister Vesna Pusic told reporters.
After the demand, nothing more was heard about Salopek until August 5 when a video of him was posted online by a group presenting itself as Islamic State in the Egyptian province of Sinai, she said.
"Money was not requested any more but (the demand was) the release of Muslim women from Egyptian jails," she said.
"It led the Egyptian (intelligence) services to the conclusion that we were talking about two organisations."
Pusic said negotiations were impossible because no contact was ever made with the Egyptian authorities.
The Islamic State group claimed on Wednesday (local time) to have beheaded Salopek, posting a picture of what it said was the victim's body on IS-affiliated Twitter accounts.
The picture's authenticity could not be immediately verified, but Croatian officials including Prime Minister Zoran Milanovic have said they feared the worst.
"At this moment we are still not sure and have no definitive confirmation either from our side or the Egyptian side that the person in the photograph posted yesterday (Wednesday) is really Tomislav Salopek," Pusic said.