A German nurse who killed his victims “out of boredom” has been charged with an additional 97 murders, potentially making him the country's deadliest serial killer.
Niels Hoegel was already serving a life sentence for murdering two patients when he was charged again by public prosecutors on Monday.
Hoegel has previously admitted to injecting patients with drugs to bring on heart failure or circulatory collapse, in order to show off his resuscitation skills to colleagues.
Arne Schmidt, a police investigator, called the killings "unique in the history of the German republic," according to German newspaper Deutsche Welle.
Hoegel was initially convicted of attempted murder and sentenced to seven and a half years in prison in 2008 after he was caught injecting a patient.
In 2015, he was jailed for life after being found guilty on two counts of murder. During the trial, he told a psychologist about the killings of 30 victims, prompting authorities to exhume 134 bodies of patients who died at the two hospitals where he worked.
Hoegel had said he intentionally brought about cardiac crises in some 90 patients at a clinic in Delmenhorst because he enjoyed the feeling of being able to resuscitate them. He later told investigators that he also killed patients at a hospital in the nearby city of Oldenburg.
Hoegel worked at the Oldenburg hospital from 1999 to 2002 and in Delmenhorst from 2003 to 2005.
Prosecutors now say investigations and toxicology reports show the accused killed a further 35 people in Oldenburg and 62 in Delmenhorst.
They say Hoegel should have been aware the drugs he was giving his patients could cause ailments ranging from possible cardiac arrhythmia, ventricular fibrillation to hypotension.
"From the prosecutorial point of view, the accused Niels H accepted, at least tacitly, in all cases the death of the patients due to the effects of the drugs," the prosecutors said in a statement.
Johann Kühme, Oldenburg police chief, said the scale of Hoegel's crimes "leaves us speechless," noting that some killings might never be proved for patients who were cremated.
"And as if all that were not enough, we must realize that the real dimension of the killings by Högel is likely many times worse," he added.
Police have said if local health officials hadn't hesitated in alerting authorities, Hoegel could have been stopped earlier.
Authorities are already pursuing criminal cases against former staff at the two medical facilities.
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