A NURSE was arrested for killing as many as 38 patients because she found them or their relatives annoying, police said.

Daniela Poggiali, a 42-year-old resident of the Italian town of Lugo, was taken into custody over the weekend and booked for the alleged slaying of 78-year-old patient Rosa Calderoni, who died from an injection of potassium.

Calderoni had been admitted to the hospital with a routine illness before she died unexpectedly.

Tests showed she died with a high amount of potassium, which can provoke cardiac arrest, in her bloodstream, according to the Central European News.

Her death triggered an investigation, which found that 38 others had died mysteriously while Poggiali was on duty, the news agency reported.

One of Poggiali’s fellow nurses described her as a "cold person but always eager to work", according to CEN.

Another one of Poggiali’s colleagues said the accused nurse was once reported for giving powerful laxatives to patients at the end of her shift to make work tougher for nurses working after her.