A woman has been arrested on suspicion of causing the deaths of four patients at a hospital in the central German state of Hesse.
She is said to have worked as an assistant anaesthetist in Fritzlar, northern Hesse, from 2015 to 2017.
Investigators allege that the 48-year-old woman falsified documents when applying for the job.
She has been in custody since Tuesday, when police raided her home and the hospital.
Prosecutors said the woman was being investigated on suspicion of manslaughter, assault, document forgery, fraud and abuse of position.
Four people died and eight others suffered health problems at the hospital due to incorrect use of anaesthetics, reports say,
The woman allegedly used anaesthetics unlawfully as she “did not possess the necessary specialist knowledge”, prosecutors said.
She is also suspected of making other mistakes, including giving patients the wrong medicine.
The investigation was first reported by German media in February. Initially, prosecutors said there was no evidence that anyone had been harmed at the hospital.
Police had then searched the hospital and removed files including old work rotas, local media in Hesse reported. The hospital said it would cooperate fully with prosecutors and police.
The suspect is said to have worked for two years as an assistant anaesthetist at Fritzlar’s Hospital of the Holy Spirit, before being moved to a different non-surgery part of the clinic until 2018. She has since moved to northern Germany.
To qualify as an anaesthetist in Germany, a six-year medical degree is required followed by another five years training in anaesthesiology.