A middle-aged female nurse with more than 20 years' experience was arrested in Italy on Thursday on suspicion of murdering 13 hospital patients, the Carabinieri police said.
Fausta Bonino, 55, worked at the intensive care ward of the hospital in Piombino, a port town in Tuscany, central Italy. The deaths took place between January 2014 and September 2015.
In a press conference, Erasmo Fontana, a commander of the Carabinieri's NAS health and safety squad, said Bonino's presumed victims were aged between 61 and 88, hospitalized for various reasons but "none in life-threatening condition."
They died after being administered unprescribed doses of Heparin, a blood thinner, another NAS commander, Gennaro Riccardi, said. Some patients had ten times the normal dosage of the drug in their blood, he added.
The drug has been used in similar hospital murder cases, notably by Czech male nurse Petr Zelanka. In 2008, he was given a life sentence in prison for murdering seven patients and attempting to kill another 10.
Bonino was shifted to another ward in October 2015. After that move, the mortality rate in her old working place dropped from 20 per cent to 12 per cent.
The woman, married with two children, was said to have worked at Piombino hospital for at least two decades, and to have received treatment for depression. She was arrested at Pisa airport upon returning from holiday with her husband.
Health Minister Beatrice Lorenzin described evidence discovered by police as "chilling, dreadful" and said Thursday's arrest "highlights once again the need to pay special care for old and fragile people who entrust their lives to healthcare facilities."