On 24 March 2003, de Berk was sentenced by the court in The Hague to life imprisonment for the murder of four patients and the attempted murder of three others. The verdict depended in part on a statistical calculation, according to which the probability was allegedly only 1 in 342 million that a nurse's shifts would coincide with so many of the deaths and resuscitations purely by chance. However, De Berk was only sentenced in cases where, according to a medical expert, other evidence was present or in which, again according to a medical expert, no natural causes could explain the incident.