A former nurse in Germany has admitted murdering 100 patients during the first day of his trial in the northern town of Oldenburg.
Detectives say Niels Högel, 41, administered fatal doses of medication to the people in his care at two hospitals in north of the country.
His motive, prosecutors say, was to impress colleagues by resuscitating the very patients he had attacked.
Högel is already serving a life term for killing people in his care.
Högel is now said to have killed 36 patients in Oldenburg and 64 in nearby Delmenhorst between 1999 and 2005.
When asked by the judge in court if the charges against him were true, Högel confessed to “more or less” all of them.
This admission makes the 41-year-old one of Germany’s worst post-war serial killers.
The current trial, which is expected to last until May, follows toxicology tests on the exhumed remains of others.
The BBC’s Jenny Hill in Berlin says the case is sensitive for German health authorities which are accused by relatives of turning a blind eye to Högel murderous activity.
Investigators say he may have killed even more but potential victims have been cremated.
“I hope he will be found guilty on each count so that the loved ones can finally find some closure,” said Petra Klein, who runs a victims’ support group.
Relatives of his alleged victims packed the court.
Högel was first caught in 2005 injecting unprescribed medication into a patient in Delmenhorst. In 2008 he was jailed for seven years for attempted murder.
In 2014-15, a second trial found him guilty of two murders and two attempted murders and he was given the maximum sentence.
He said he was “honestly sorry” and hoped families would find peace. He said the decisions to carry out his crimes had been “relatively spontaneous”.
However, during the trial he confessed to a psychiatrist that he had killed up to 30 people.
Investigators then widened the investigation, exhuming 130 former patients and looking for evidence of medication that could have triggered cardiac arrest. They also pored over records in the hospitals he worked at.
Records at the Oldenburg hospital showed rates of deaths and resuscitations had more than doubled when Högel was on shift, German media reported.