|The handcuffed ex-nurse covers his face with a folder in a courtroom of the regional court in Oldenburg, northern Germany|
A psychiatric expert told the trial that the 38-year-old defendant had confessed to the killings during recently held assessments, a court spokesman said.
The ex-nurse went on trial in Oldenburg in northern Germany in September, accused of the murder of three patients and attempted murder of two others.
The expert said the defendant had admitted to those charges, as well as saying he had over-medicated another 90 patients, 30 of whom died, the spokesman said.
Investigators suspect his motive was to spark medical emergencies for patients so that he could then demonstrate his resuscitation skills, but that he also acted out of boredom.
The deaths occurred at Delmenhorst clinic, located near Oldenburg in Lower Saxony state, where the accused worked in the intensive care unit between 2003 and 2005.
He is believed to have injected patients with a heart medication that disturbed the heart rhythm and caused a drop in blood pressure.
The psychiatric expert said the man, who had previously worked in other clinics, at an elderly home and for emergency medical services, said he had not carried out killings elsewhere, the spokesman said.
He met the defendant four times recently