The Italian newspaper Corriere della Sera quoted one of Ms Poggiali's colleagues as saying that in the case of difficult patients, the suspect would say: "Leave it to me, I'll quieten them."
It has also emerged that in March this year, a week before Ms Calderoni's death, an elderly relative of the hospital's director of nursing, Mauro Taglioni, also died. Reports suggest Ms Poggiali did not enjoy a good relationship with her boss, and that the death of his relative is being investigated.
It is claimed that Ms Poggiali even took ghoulish selfies. The Libero Quotidiano newspaper said that Ms Poggiali photographed herself on her smartphone while standing next to one of her suspected victims, moments after he had died.
"In all my professional years of seeing shocking photos, there have been few like these," said Alessandro Mancini, the chief prosecutor of Ravenna.
Colleagues said Ms Poggiali deliberately gave laxatives to patients at the end of her shift so that other nurses would have to deal with the effects.
- The Independent