Former nurse Niels Hoegel, accused of killing more than 100 patients in his care, went on trial Tuesday in the biggest serial killing case in Germany's post-war history.
Hoegel, 41, has already spent nearly a decade in prison on a life term for other patient deaths, and is accused of intentionally administering medical overdoses to victims so he could bring them back to life at the last moment.
As the proceedings opened in the northern city of Oldenburg, presiding judge Sebastian Buehrmann said the main aim of the trial was to establish the full scope of the murder spree that was allowed to go unchecked for years at two German hospitals.
"We will do our utmost to learn the truth," he said. "It is like a house with dark rooms -- we want to bring light into the darkness."
The bearded, heavyset Hoegel took his seat in the courtroom wearing a hoodie and covered his face with a folder as long as photographers and camera teams were allowed to remain.
After a minute of silence for the victims, Hoegel listened impassively, his head lowered, as public prosecutor Daniela Schiereck-Bohlmann read out the name of each patient and the charges against the defendant.
During the trial set to last until at least May, he is to face questioning before dozens of victims' anguished loved ones.
Prosecutors say at least 36 patients were killed at a hospital in Oldenburg where he worked, and about 64 more at a clinic in nearby Delmenhorst, between 2000 and 2005.
More than 130 bodies of patients who died on Hoegel's watch have been exhumed, in a case investigators have called "unprecedented in Germany to our knowledge".
One of the more than 100 co-plaintiffs in the trial, Christian Marbach, said it was a scandal that Hoegel had been allowed to kill with impunity for such an extended period of time without hospital authorities or law enforcement intervening.
"They had everything they needed (to stop him) -- you don't have to be Sherlock Holmes," Marbach, the grandson of one of the patients, told AFP.
"I am basically looking for answers, and for justice," said Frank Brinkers, whose father was among the alleged victims.
Caught in 2005 while injecting an unprescribed medication into a patient in Delmenhorst, Hoegel was sentenced in 2008 to seven years in prison for attempted murder.
A second trial followed in 2014-15 under pressure from alleged victims' families, who accused prosecutors of dragging their feet.
He was found guilty of murder and attempted murder of five other victims and given the maximum sentence of 15 years.
It was then that Hoegel confessed to his psychiatrist at least 30 more murders committed in Delmenhorst. That prompted investigators to take a closer look at suspicious deaths in Oldenburg.
Investigators say the final toll could top 200 but fear they might never know for sure because the bodies of many potential victims were cremated.
Hoegel appears to have followed a similar procedure each time, first injecting a medication that triggered cardiac arrest, followed by an often futile attempt at resuscitation.
Prosecutors say he was motivated by vanity, to show off his skills at saving human lives, and by simple "boredom".
The choice of victim appears to have been entirely random, with their ages ranging from 34 to 96.
Killing in itself was never his aim, according to one psychologist who evaluated him.
When he managed to revive a patient, he was sated, but only for a few days, the expert said, adding: "For him, it was like a drug."
Oldenburg, Germany | AFP