(ANSA) - Bujumbura, September 8 - Three Italian nuns murdered while working as missionaries in the African nation of Burundi were raped and one decapitated, according to media reports on Monday. Godefroid Bizimana, vice director general of the Burundi police said that Bernadette Boggian was found to have been beheaded. Earlier, the foreign ministry in Rome confirmed that the three Italians, part of the Xaverian order, were killed at their convent in the city of Kamenge. Police were searching for a motive for the killings of Boggian, 79, Luci Pulici, 75, and Olga Raschietti, 82, with a botched robbery attempt one early theory.

Two of the three Italian nuns were found with their throats slit, an anonymous police official was quoted as saying by media. Kamenge Mayor Damien Baseka said that two of the nuns had been killed "savagely". The bodies of Pulici and Raschietti, were found on Sunday afternoon, leading to early reports that two nuns had been killed.

Boggian's body was found later the same day.

Pope Francis sent his condolences to the victims' religious order.

"Deeply saddened by the tragic deaths of the Xaverian missionary sisters killed in Burundi, the Holy Father wishes to assure his heartfelt participation in the profound suffering of the congregation for the loss of such dedicated sisters and, in the hope that the blood they have shed may become the seed of hope to build true fraternity between peoples, he raises fervent prayers for the eternal repose of their souls and for their generous witness of the gospel," read the message to the Xaverian order from the pope.

"To their families, the entire institute and those who mourn their loss, he imparts the comfort of his apostolic blessing," said the papal message. Italian Foreign Minister Federica Mogherini expressed condolences and said the murders brought "great pain".

"We're once again witness to the sacrifices made by those who, with complete dedication, spend their entire lives relieving the overwhelming suffering that still exists in Africa," Mogherini said.

Vatican Radio said the three nuns had been working among the sick and poor in Burundi, a small central African state, for seven years. Prior to that, they had been missionaries in the Democratic Republic of Congo. Raschietti had spent 50 years in Africa.

