An ex-German nurse who is serving a life term for killing patients by injecting them with lethal medication is suspected to have killed more than 100 people. In 2015, 41-year-old Niels Hoegel was convicted of two murders and four attempted murders of patients admitted to Intensive Care Unit (ICU) at Delmenhorst hospital near Bremen city. However, the later investigations unveiled that scores of patients were killed by him during his tenure at the hospital. The number may rise further as toxicology studies are currently underway for five other cases and exhumations of three other former patients.

According to reports, Niels Hoegel has admitted to his crime of injecting patients with lethal drugs that can result in heart failure or circulatory collapse. The nurse revealed that he first injected patients with fatal drugs and then tried to revive them to get accolades from his medical peers. He said that he indulged in the heinous act out of boredom and felt good when he was able to revive the patients and felt broken when he was unable to do so.

The insights we were able to gain are terrifying, they surpass what we could have imagined,” Johann Kuehme, Oldenburg police chief told the media. “He cannot remember every case, but in more than 30 he concretely remembered the patients and his behaviour,” Daniela Schiereck-Bohlemann, prosecutor in the case revealed.

Although, the exact number of people that Hoegel killed might never be known, he is certainly set to go down in history as one of the worst serial killers. During his trial in the year 2015, the former nurse confessed to killing more patients in his career, prompting police to set up a special commission to probe into deaths at two clinics where he worked. Prosecutors have hinted at plans to bring more charges against him next year.