A 22-year-old nurse from Rotterdam has been charged with murdering six patients and attempting to kill six more by giving them overdoses of insulin.

Prosecutors investigated 15 suspicious deaths of patients at nursing homes where Rahiied A. worked as a trainee or locum nurse between January 2016 and November 2017, NOS reported. In three cases no charges were brought because investigators could not establish his involvement.

A.’s work included evening and weekend shifts when he was alone with patients. Concerns first arose after a female resident in one of the care homes became seriously ill and was taken to hospital, where doctors found a high quantity of insulin in her blood.

The details emerged during a procedural hearing in the case, which has been ongoing since A. was arrested last year. At least three bodies of people who lived in the nursing homes in Rotterdam, Puttershoek and Ridderkerk have been disinterred during the investigation.

A. is also accused of stealing medicines and medical documents and falsifying his ‘declaration of behaviour’ (Verklaring Omtrent Gedrag), which is a prerequisite for jobs that involve working with vulnerable people.

Prosecution service spokesman Ernst Pols said A.’s motivation for the alleged killings had not been discussed in court. ‘The suspect has talked to the police, but exactly what was said will be revealed during the substantial court hearings in the case next year,’ he said.