Criminal investigations have been launched into four cases of euthanasia in the Netherlands after a sharp rise in the number of doctor-assisted deaths, reports the Guardian newspaper. The cases follow the opening of a criminal inquiry last year into the euthanasia of a 74-year-old woman who was described by prosecutors as “seriously demented” and legally incapable of choosing whether to die or not.

The law in the Netherlands changed in 2002 to allow doctors to end the life, on request, of people in “unbearable suffering”, for whom there is no prospect of improvement. About 7,000 people were euthanised by doctors in 2017, according to official records, up from 4,188 five years ago. Despite this rise in numbers, there is yet to be a single prosecution of a doctor involved but concerns have been raised that assisted death is becoming normalised.

The four cases being investigated have been referred to the prosecutor’s office by regional euthanasia committees and alleged they had found problems. The cases were then found to warrant criminal investigation.