On June 22, 2005, colleagues at the Delmenhorst clinic in Lower Saxony caught a nurse named Niels Högel deliberately manipulating a patient's syringe pump to give ajmaline, a heart drug no doctor had prescribed. For more than two years emergencies and deaths, mostly from arrhythmia or sudden falls in blood pressure, had spiked on his shifts. Some coworkers had distanced themselves from him, and four empty vials of ajmaline had turned up on his ward, but his superiors did not act. He was arrested that summer. When police examined every death at the hospital from 2003 to 2005, they found the death rate had doubled while he worked there, and that seventy-three percent of the deaths in 2005 matched his schedule.
He was born on December 30, 1976, in Wilhelmshaven. His father was a nurse at the Sankt-Willehad hospital there and his grandmother had also been a nurse; his mother was a paralegal, and he has an older sister. He has described a sheltered childhood without violence at home. He trained at the Sankt-Willehad hospital, qualified in 1997 and stayed on there.
From 1999 he worked in the cardiac surgery intensive care unit, Ward 211, at the Oldenburg clinic. In August 2001 its doctors and orderlies met, with Högel present, to discuss a spike in resuscitations and deaths, and found that fifty-eight percent of the incidents had happened on his shifts. He called in sick for three weeks, during which only two patients on the ward died. He later said he had thought at the time that he had been found out. The head physician moved him to anesthesiology, where the head of that department soon grew suspicious of how often he was present at emergencies. In September 2002 the clinic's head physician confronted him and offered him three months' full pay to resign, or a transfer to moving patients around the hospital. On October 10, 2002, the director of nursing gave him a reference praising his circumspect, diligent and autonomous work, his prudent conduct in critical situations, and the utmost satisfaction with which he had done his job. In December 2002 he started at Delmenhorst.
He injected patients with ajmaline, sotalol, lidocaine, amiodarone or calcium chloride, which in overdose cause arrhythmia and collapsing blood pressure, and then took part in the attempt to revive them. Prosecutors said he did it out of boredom and to show off his resuscitation skills; the court later called his motive, to emerge as a hero, base. He married in 2004, and in July his daughter was born. To sustain "this euphoria, this feeling of happiness," he said, he injected a gravely ill patient on his first night back on duty after the birth. He had a history of alcohol and painkiller abuse. A 2019 psychiatric evaluation found a combined personality disorder with narcissistic, antisocial and compulsive features, a strong need for recognition, a craving for excitement and a remarkable lack of empathy, guilt and remorse, and put the chance of successful therapy as very, very low.
In December 2006 the Oldenburg regional court gave him five years for attempted manslaughter in the June 2005 case. A joint plaintiff appealed, the verdict was overturned, and in June 2008 he received seven and a half years and a lifetime ban from working in his profession. In September 2014 he was charged with three murders and two attempted murders at Delmenhorst. He confessed, said he had committed thirty more killings, and on February 28, 2015, he was sentenced to life.
Police launched a major investigation in October 2014, and from November a special commission named Kardio reviewed every death at the places he had worked. It reexamined more than two hundred cases and exhumed and autopsied 134 bodies from sixty-seven cemeteries in Germany, Poland and Turkey. In many the remains were too decomposed to show traces of drugs, and 101 patients who died at Delmenhorst in his time there had been cremated. In January 2018 prosecutors charged him with murdering one hundred patients, aged thirty-four to ninety-six, between February 7, 2000, and June 24, 2005. The trial opened on October 30, 2018, in the Weser-Ems-Hallen, a conference center in Oldenburg, because there were 120 joint plaintiffs. On the first day he confessed to forty-three killings, said he could not remember fifty-two and denied five. On June 6, 2019, the court convicted him of eighty-five murders, acquitted him of fifteen, and sentenced him to life with a finding of particular gravity of guilt, which rules out release after the usual minimum of fifteen years. The Federal Court of Justice dismissed his appeal on September 11, 2020.
The head of the Kardio commission called the provable killings only the tip of the iceberg, and investigators have estimated that he may have killed as many as three hundred people in just over five years. A former Oldenburg chief prosecutor was charged in 2015 with obstruction of justice for failing to act on evidence against him; the case was dismissed. Both clinics promised compensation and introduced a second, independent examination of the dead. In February 2022 seven of his former supervisors went on trial in Oldenburg, accused of suspecting him and doing nothing to protect their hospitals' reputations. In September 2022 all seven were acquitted, at the request of both prosecution and defense.