Hopes for the safe return of a Jesuit missionary abducted in Syria last month have dramatically receded, after his killing was reported by a prominent activist group.
The Britain-based Syrian Observatory for Human Rights claims Father Paolo Dall'Oglio has been executed by jihadist rebels in the city of ar-Raqqah, although the Italian foreign ministry has still not confirmed the report.
"Activists in the city, and who are close to Father Paolo, have confirmed to the SOHR that Italian Jesuit priest and the messenger of peace Father Paolo Dall'Oglio has been killed while in the prisons of the ISIS [Islamic State of Iraq and Levante], where he has been held for over two weeks," the SOHR said.
"The Syrian Observatory strongly urges all sides of the Syrian opposition to put pressure on the ISIS to uncover the fate of Father Paolo Dall'Oglio, and if it is the case to give his body so that he can be buried in the traditions of his church and family.
"We demand that all those responsible be held accountable and brought to justice."
Rome native Dall'Oglio, 58, vanished in the rebel-held northern city on July 29.
He was reportedly taken hostage by the Islamic State of Iraq and the Levant (ISIS), a group closely connected with the better-known Islamist al-Nusra Front, although the terrorist cell never confirmed the claim.
Dall'Oglio had been a Jesuit missionary to Syria since the early 1980s and was reportedly loved by the local population.
Protesters have been demonstrating almost every day outside the ISIS headquarters in ar-Raqqah, demanding his and other prisoners' release.
"Father Paolo is known for his support for the Syrian people in their demands for freedom and dignity," SOHR said.
"He has worked wholeheartedly to foster understanding and reconciliation in Syria, as well as to raise awareness of the plight of Syrians abroad."
The clergyman had voluntarily approached ISIS at their headquarters to negotiate the release of some hostages and broker a truce between Islamist rebels and local Kurds.
"He also wanted to negotiate their [ISIS] vision of the state," Syrian opposition activist Salam Kawakibi, deputy director at Arab Reform, told IBTimes UK.
ISIS fight to create an Islamic state in Syria. "The majority of fighters are not Syrian and their agenda is not that of the Syrian people," Kawakibi added.
"They don't know that in this society Christians and Muslims lived for thousands of years without any conflict; they came from abroad with very extreme visions to build their own society."
Kawakibi said Dall'Oglio last got in touch with a young activist with whom he was very close less than a week ago via SMS, saying he was well and alive and was continuing his talks with ISIS.
"Dall'Oglio strongly believed that he could through peaceful dialogue find common ground with them and change their vision."
A vocal critic of the Syrian regime led by President Bashar al-Assad, Dall'oglio was expelled from the country by government authorities in June 2012 but re-entered in January.
His death was first reported by another prominent rebel activist, Lama al-Atassi, secretary-general of the Syrian National Front, earlier this week but was disputed by other sources.