OLDENBURG, Germany (NYTIMES) - The former nurse's crimes were "incomprehensible," a German judge told the court on Thursday (June 6), reaching his arms across the breadth of the bench as if to capture in one gesture what he sensed his words had failed to define - the enormity of murdering 85 patients who had been placed in the care of the nurse but instead had found death.

"Your guilt is so large that one can't explain it," the presiding judge, Sebastian Buhrmann, told the nurse, Niels Hogel, in a courtroom packed with the relatives of the 100 patients whose deaths he was charged with orchestrating.

"It is so large, you can't show it."

Hogel is believed to be the most prolific serial killer in peacetime Germany, and perhaps the world. His trial in the 85 murders sought to provide a measure of comfort and answers to some of the victims' families, more than a decade after they died. His conviction on Thursday was the third for the nurse.

Officials suspect Hogel may have killed as many as 300 patients while working at two clinics in northern Germany from 2000 to 2005.

He was accused of administering overdoses of drugs that caused cardiac arrest so that he could try to revive patients heroically. His colleagues called him "Resuscitation Rambo."

In its sentencing, the court barred Hogel from working as a nurse, emergency medical responder or any other job providing care.

"We want to be sure that you never, ever again are able to work in such a job," the judge said.

From the trial's opening in October, Buhrmann had stressed that the purpose went beyond trying to determine guilt: It was to try to find answers to how and why the patients had died. But he acknowledged that in 15 cases, the court had failed to find enough evidence to support murder convictions.

"Despite all of our attempts, we could only lift part of the fog that hangs this trial," he said. "That fills us with a certain sadness."

Throughout the more than 90 minutes that the judge read out the sentencing, he repeatedly and directly addressed Hogel. The former nurse, dressed in a black T-shirt and wearing a thick chain necklace, sat with his head resting in the palm of his right hand, listening passively.

"The human ability to understand capitulates when faced with the sheer number of deaths, week for week, month for month, year for year," Buhrmann said.

In the early days of the trial, going through the names of each patient, their medical records and the details of how and when they had died left him feeling "like a bookkeeper of death," he said.

Hogel had confessed to killing 43 of his patients, and spent the early days of the trial going through the medical files of each of the 100 patients with the judge. For most of the others he told the court that he could not remember, or could not rule out, murdering the patients. He denied five charges outright.

The court, citing his past behaviour and expert testimony, questioned whether Hogel's statements had been truthful.

"The most difficult part was evaluating what you said," the judge told him, citing specific cases where written evidence contradicted the former nurse's testimony. "You didn't always tell the truth, and that makes it so difficult," the judge said.

Under German law, a person convicted of murder can be sentenced only to life in prison with the possibility of parole after 15 years, depending on the severity of the crime. Hogel is already serving a life sentence for other murders, and the judge made clear that his record would ensure that he would not be eligible for early parole.

Citing the US justice system, where for each death a life sentence is handed down, the judge said that even if Hogel were to serve 15 years for each of the 85 murders, it would add up to 1,275 years in prison.

"That is an indication of what I call incomprehensible," he said.

The judge also said that Hogel's "complex bundle of motives" was also proving challenging to understand. He cited psychologist testimony and assessments that the former nurse was a narcissist who liked to cast himself as a hero.

"You lacked empathy and depersonalised those whose deaths you caused," Buhrmann said.

Prosecutors had sought to charge Hogel with 97 murders, but the defense argued that only 55 cases had been proved beyond a doubt. The defence said that Hogel should be found guilty of attempted murder in 14 cases and acquitted of an additional 31.

The verdict can be appealed, but Hogel's defence team did not indicate whether they would do so.

The true number of murders may never be known. Reluctance on the part of the directors of the first hospital where he worked, in Oldenburg, Germany, to alert authorities to their suspicions, followed by the reluctance of previous state prosectors to take up the case once the second hospital did alert them, cost precious time and evidence.

"That was time we can't get back," Buhrmann said. "Years passed and evidence was lost."

Many witnesses could not remember, he added, while others deliberately sought to hide information.

In his ruling, the judge condemned the director of the main Oldenburg hospital by name for failing to take action that could have stopped Hogel and saved lives. Instead, the hospital moved him first to a different ward, then wrote him a glowing recommendation and let him go. Weeks later, he took his next job in a hospital in nearby Delmenhorst, about 30km away. There, he continued killing.

Buhrmann ordered eight of Hogel's former colleagues to be investigated on perjury because of suspicion they had lied to the court or had withheld evidence in the most recent trial. Two doctors and two head nurses from the Delmenhorst hospital have been charged with manslaughter, and authorities are investigating other hospital employees, also from Oldenburg. Högel could be called to testify in those trials.

After closing arguments Wednesday, Högel read a prepared apology to the packed courtroom.

"I would like to sincerely apologise for what I have done to each and every one of you," he said.

For family members, his attempt at an apology fell flat.

"He's a liar through and through," said Christian Marbach, whose grandfather was found to be a victim of Högel in a previous trial and had followed the recent proceedings.

More important, he said, is that other criminal investigations against the doctors and head nurses from the clinics where Hogel worked and was allowed to kill would now be allowed to proceed.

"The wall of silence has been broken," Marbach said.

"Now it is very important that those who were in positions of power be brought to justice."