German nurse suspected to have killed at least 106 patients out of 'boredom'

Niels Hoegel, who is already serving a life sentence for six murders, is suspected of killing the patients during his time working at two clinics in northern Germany.

Police are investigating 100 additional deaths.

After announcing  scores more killings in August, on Thursday prosecutors in the northern city of Oldenburg said toxicologies had identified a further 16 deaths that the nurse may have caused, though they cautioned that they had not necessarily stopped counting yet.

"It could be more," chief prosecutor Martin Kozoliek has been quoted by Deutsche Welle  on Thursday.

A court sentenced Niels H. to life in prison in 2015 for two counts of murder and four of attempted murder. German media, who began identifying the nurse after the initial guilty verdict, have resumed calling him by his first name and last initial because he has not yet gone to trial for the new deaths.

During his 2015 trial, Niels said he had murdered even more patients than initially suspected, injecting them with pharmaceuticals that can cause heart failure or circulatory collapse and trying to revive them to impress his medical peers.

He testified that he acted "out of boredom" at times, feeling euphoric when he managed to bring a patient back to life and devastated when he failed.

Following that admission, experts exhumed more 134 bodies to test them for traces of drugs.

Earlier this year, investigators said the nurse might have killed an additional 24 people. By August, police were implicating the 41-year-old in at least 90 murders — a death toll "unique in the history of the German republic," in the words of chief police investigator Arne Schmidt.