Three Italian nuns were killed in their Burundi convent on Sunday, according to reports from the Associated Press and the BBC. Police have detained two suspects in the crime, and the Catholic diocese of Parma, Italy said in a statement that the deaths are "the tragic outcome of an armed robbery by a mentally unbalanced person."

The nuns—Lucia Pulici, 75, Olga Raschietti, 82, and Bernadetta Boggian, 79—were missionaries near Kamenge in Burundi. According to the nuns' superior, Rev. Mario Pulcini, two of the nuns were killed Sunday afternoon, and the third nun was killed after she discovered their bodies.

The BBC notes that in 2011, a Croatian nun and an Italian aid worker were killed in a robbery in Burundi.

[Photo via AP]