A hospital ward is built around trust. Patients cannot check what is in the syringe, and families cannot check who is holding it. When a nurse or a doctor abuses that, the question that follows is rarely about the person alone. It is about how long the people around them took to see it, and what the law did once it did. Seven cases from Germany, the Czech Republic, England, India and the United States show five different systems answering that question, some quickly, most slowly, and none of them comfortably.
Niels Högel worked as an intensive care nurse in Lower Saxony, in northwestern Germany. The Landgericht Oldenburg held in June 2019 that he had given patients heart medication that no doctor had ordered, so that their hearts or circulation failed, and that he then joined the effort to revive them. The court accepted that he wanted the praise a successful resuscitation brought. Most of the patients died.
On June 6, 2019, the court convicted him of 85 murders committed between 2000 and 2005 at the hospitals in Oldenburg and nearby Delmenhorst, and sentenced him to life. It acquitted him of 15 more for lack of evidence. He had been convicted twice before, in 2008 and 2015, for offenses against six other patients. The Associated Press called him believed to be modern Germany’s most prolific serial killer. In 2018 he had confessed to 43 of the 100 killings then charged, said he could not remember 52 and denied five. Investigators put the possible total above 200, and said it might never be known, because many patients who died on his shifts had been cremated before anyone suspected him.
The case turned as much on what the hospitals did as on what he did. Staff in Oldenburg had kept a tally of the nurses on duty at resuscitations and deaths; in 2001 his name carried the most marks, 18, the taz reported. A handwritten note on the list said that suspicions were not enough to inform prosecutors. In 2002, according to the later indictment of his superiors, hospital leadership released him from work on full pay for three months, and he was given a choice between doing only transport and errands or leaving. He left with a good reference. Prosecutors later called it false, because it concealed the danger he posed. With it, he was hired at the hospital in Delmenhorst.
He was not stopped there by management either. In June 2005 a colleague caught him giving a patient a drug that had not been prescribed. The head of the later police special commission said he went on working late shifts until his vacation began, and that his last known killing came on June 24, 2005, two days after he had been caught in the act with another patient. Högel himself told the court in 2022 that he no longer tried to hide what he was doing and half hoped to be caught.
The justice that followed was slow and in pieces. In December 2006 the Landgericht Oldenburg convicted him of attempted manslaughter and sentenced him to five years; the Bundesgerichtshof overturned that. A retrial in summer 2008 produced a conviction for attempted murder and a sentence of seven and a half years (AFP reported seven) with a lifetime professional ban. The hospital had at first refused to name patients, citing data protection, and police received its death figures only in 2006. The Oldenburg prosecutor’s office later apologized publicly for the delays. In February 2015 he received life with particular gravity of guilt for murder; during that trial he told the court that he had been responsible for about 90 acts, and the Oldenburg police opened a special commission to examine more than 200 suspected cases at all his former workplaces.
Then Germany did something few countries have done: it put the managers on trial. Seven of his former superiors and colleagues were tried over their part, and in October 2022 they were acquitted, because intent could not be shown. The Bundesgerichtshof rejected his appeal against the 2019 verdict in September 2020, and on March 17, 2026 the Landgericht Oldenburg fixed his minimum term at 28 years. Lower Saxony changed its hospital law in October 2018, and ward pharmacists became mandatory in its hospitals at the start of 2022, according to APOTHEKE ADHOC.
The pattern at Havlíčkův Brod was caught by arithmetic. Petr Zelenka was a nurse and later head nurse on the anesthesiology and resuscitation ward of the hospital, a town in the Vysočina Region. Between May and September 2006 he gave patients a medicine that no doctor had prescribed for them. Seven died and ten survived. Months passed before anyone connected the run of sudden bleeding on the ward to one member of staff, Radio Prague and Aktuálně.cz both reported.
Pavel Longin, the ward’s head physician, laid the duty roster beside the records of bleeding, Czech Television reported. He counted about 40 unexplained cases; in 23 of them the medicine had been involved, and Zelenka was on duty for all 23. On September 25, 2006 the hospital ended his employment by mutual agreement. Critics said that choice, a negotiated exit in place of a dismissal, let him find work at another hospital, in Jihlava. The health minister, Tomáš Julínek, said a dismissal would probably have prevented it. Zelenka worked at the Jihlava hospital for about a month, and Radio Prague reported that he had no opportunity to harm anyone there.
The hospital’s complaint then waited. The prosecutor’s office received it on October 17, 2006 and the police a few days later. It was filed against an unknown perpetrator and, the minister said, spoke of an unknown harmful substance without naming the medicine or the nurse. The investigator who took it judged it not urgent and then fell ill for three weeks. Only when the investigator returned on November 27 did the police take the case up in earnest, and on November 30 Longin gave a statement naming Zelenka. A police inspection in Hradec Králové concluded in December 2006 that officers in Havlíčkův Brod had made an error and that poor organization had cost three weeks, and the police president admitted delays. Zelenka was arrested on December 1, 2006, at the hospital in Jihlava.
The trial was brisk. On February 21, 2008, the Regional Court in Hradec Králové convicted him of seven murders and ten attempted murders and sentenced him to life in a high-security prison. The presiding judge said that if the death penalty had not been abolished in 1990 he would have imposed it. The High Court in Prague confirmed the verdict on June 11, 2008, and the Supreme Court and the Constitutional Court later turned down his last challenges. He may first apply for conditional release in 2038.
The institutions fared differently from the nurse. The hospital’s director was prosecuted for failing to report: Radio Prague carried the headline on July 31, 2008 that he had been sentenced to prison, and he was finally acquitted. Relatives of patients spent more than a decade in the civil courts. A court held in 2011 that the hospital did not have to pay compensation, and in May 2020 the Constitutional Court rejected a complaint seeking millions of crowns for a victim’s survivors. A doctor told TN.cz years later that the drug is now strictly controlled on wards.
Colin Norris, a Glasgow-born staff nurse in his first year after qualifying, worked on orthopedic wards in Leeds in 2002, where five elderly women recovering from hip fractures fell into unexplained hypoglycemia, a dangerous drop in blood sugar. None had diabetes. Four died. The last, Ethel Hall, 86, was tested in time: her blood showed about 12 times the normal level of insulin, press reports of the trial said. Police then examined the earlier cases in which patients without diabetes had gone into comas on his shifts, and the review led to the four earlier women.
In March 2008, after a five-month trial at Newcastle upon Tyne Crown Court, a jury convicted him by a majority of 11 to 1 of four murders and one attempted murder. He was sentenced on March 4, 2008 to life with a minimum of 30 years. He has denied everything. The case has been fought since then over medical science: whether severe hypoglycemia in frail, elderly hospital patients is as rare as the experts at his trial said. The Court of Appeal rejected his first appeal in December 2009. In February 2021 the Criminal Cases Review Commission sent the case back on fresh expert evidence, and on June 26, 2025 the Court of Appeal, having heard that evidence, upheld all five convictions. In September 2025 it refused to certify a point of law for the Supreme Court. He is now named in the law reports as Colin Campbell, formerly Colin Norris.
This is the system’s other face. In Germany and the Czech Republic the argument was about institutions that knew too much and said too little. In Leeds the institution acted on one test result, a jury accepted the Crown’s account, and the only continuing dispute is whether the scientific premise of the whole prosecution holds. The Criminal Cases Review Commission wrote that there was no dispute that Hall had been murdered with insulin. The argument is about the other four.
Devender Kumar Sharma holds a degree in Ayurvedic medicine and surgery and has been called "Doctor Death" by Indian police and newspapers. According to the Press Trust of India in 2025, courts in Delhi, Rajasthan and Haryana have sentenced him to life in seven murder cases, and a court in Gurgaon sentenced him to death in one. The cases belong to a gang’s killings of taxi and truck drivers between 2002 and 2004, whose vehicles were then sold. He was arrested in 2004, in connection with both those killings and an illegal kidney transplant racket in Gurgaon, which police describe as a separate enterprise. Police told reporters he claimed to have arranged more than 125 illegal transplants.
The numbers around him are loose. He told police he had killed more than 50 people and had lost count. Police records, the Tribune reported, link him to at least 21 drivers. Reports of more than 100 killings circulated in 2020, and a Delhi police officer said then they could not be confirmed, because the cases were investigated separately by the police of four states. Convictions are in six or seven cases, depending on whether police or the news agency is counted. None of the larger figures is a court finding.
What distinguishes the case among these seven is what happened after sentencing. In July 2020 Delhi police re-arrested him in Baprola after he jumped parole. He had been serving a life sentence in Jaipur and had spent about 16 years in prison, PTI reported. A false claim spread after that arrest, that he had removed kidneys from healthy people by wrongly declaring them positive for COVID-19; the fact-checking site Alt News rated it false on August 5, 2020. He was out again by June 2023, when he was paroled for two months in a Delhi case, and he did not return after August 3, 2023. In May 2025 police located him in Dausa, Rajasthan, living at a temple ashram as a priest, running an unlicensed clinic and taking donations. As of May 21, 2025 he had been handed over to jail authorities. Here the question is not how long a hospital took to notice. It is how a man with multiple life sentences came to be released on parole twice.
The American cases differ from the others in how they were proved, and in the weight of the punishment.
Kristen Gilbert was a registered nurse on the evening shift at a veterans hospital in the Leeds section of Northampton, Massachusetts. In March 2001 a federal jury in Springfield convicted her of murdering four patients, three counts in the first degree and one in the second, and of attempting to murder others. Prosecutors said she injected the men with a heart stimulant to bring on cardiac emergencies, and that she did it for the attention they brought her. The case was federal because the hospital stands on federal land. The government asked for death in a state that had abolished it. On March 26, 2001 the penalty jury did not impose it, and she was sentenced to life without parole.
Her path through the courts had begun earlier and elsewhere. In 1998 she was sentenced to 15 months for telephoning a bomb threat to the same hospital in September 1996, while a grand jury was looking at the deaths on her ward; the First Circuit affirmed in June 1999. The appeals court also ruled, in October 2000, on a different question: whether jurors could hear about the illness of her husband in November 1995. The trial judge had excluded it, the First Circuit affirmed, and it called the evidence "undeniably explosive," because of the inference it invited, that a woman who would try to kill her husband would kill her patients. It was never charged, and it stayed an allegation.
Heather Pressdee’s case is the nearest to the German one in scale and the furthest in structure. She was a registered nurse who moved through around 11 care facilities in western Pennsylvania between 2018 and 2023, and who gave patients insulin they did not need, mostly on overnight shifts. She was arrested in May 2023 over three patients at a facility in Chicora. In November 2023 the Pennsylvania Attorney General’s office charged her over 19 more. On May 2, 2024, in Butler County, she pleaded guilty to three counts of first-degree murder and 19 of attempted murder, covering 22 patients. Prosecutors said 17 of them died, and that they charged murder only where physical evidence supported the cause of death. She was sentenced the same day to three consecutive life terms without parole plus 380 to 760 years. Asked in court why she was pleading guilty, she said, "Because I am guilty."
The gap between the legal record and the death count mattered to the families, and so did the record that came before it. Investigators said she had worked at 11 facilities since 2018. Lawyers for families said that before one facility hired her in April 2021, she had been fired or forced to resign from six others in under three years. The lawsuits are allegations that have not been tried. A warning did reach the state: in February 2022 a hospital doctor alerted officials after treating two patients for low blood sugar who had her listed as their nurse, WPXI reported, and the state’s departments made a joint referral to the Attorney General’s office only in December 2022. At least six residents died in that interval, WPXI reported. In June 2024 state lawmakers were considering legislation to protect patients.
Robert Rubane Diaz is the oldest of the American cases and the one that changed a rule of procedure. In March and April 1981 patients died at night in a small intensive care unit in Perris, California, and Diaz, a night-shift nurse, was on duty for every one of the deaths the state charged. He was charged with 12 murders, 11 at the Perris hospital and one at a hospital in Banning where he worked briefly after the Perris unit closed. Prosecutors said he gave them massive overdoses of lidocaine, a heart-rhythm drug. He waived a jury. Judge John H. Barnard of the Riverside County Superior Court convicted him of 12 counts of first-degree murder and imposed a judgment of death. On August 31, 1992 the California Supreme Court affirmed, calling the use of lidocaine to kill intensive care patients "unprecedented," and holding that the evidence pointed "unerringly" to him.
The case left a second mark. The 41-day preliminary hearing at which he was ordered to stand trial was closed to the press and public at his request, and a newspaper publisher’s challenge reached the United States Supreme Court. In 1986 the Court ruled that the public has a qualified First Amendment right to attend such hearings. Diaz supplied the facts; the press supplied the principle.
Laid side by side, the cases separate into three questions: who noticed, who acted, and what the law could do.
Noticing was done by people at the bedside in nearly every case: a Delmenhorst colleague in 2005, a head physician with a roster in Havlíčkův Brod, a doctor who ordered an insulin test in Leeds, nurses who watched a pattern in Perris and in Northampton, a hospital physician in Pennsylvania in 2022. Acting is where the systems part company. Oldenburg’s managers and Havlíčkův Brod’s director chose quiet exits, and in both places a nurse went on working somewhere else. Pennsylvania’s regulators took ten months between a doctor’s warning and a referral. Leeds moved on a laboratory result.
The law’s answers vary even more. Germany has no death penalty and tried superiors, and acquitted them. The Czech Republic, without capital punishment since 1990, gave life with a first parole application 32 years after the first death. The United States asked for death in Massachusetts and did not get it, got it in California in 1984, and secured guilty pleas in Pennsylvania that spared the families a trial. India’s courts sentenced one man to death and several times to life, and still could not keep him inside. England, with no death penalty and no confession to rest on, gave a 30 year minimum and has spent 17 years defending the science.
What the cases do not show is a single profile. Some of these nurses were praised, some were disciplined at every job. One was a doctor of Ayurvedic medicine whose convictions concern drivers, not patients; he belongs with the others by his profession and by the questions his case raises. What they share is narrower and harder to fix: a place where a pattern could be seen, an interval before anyone acted on it, and a record that the next employer or the next hospital did not read.
• 1981 (March and April): Deaths on the night shift of an intensive care unit in Perris, California; Robert Diaz later charged with 12 murders.
• 1984 (December): Diaz tried by judge sitting alone; judgment of death.
• 1986 (June 30): United States Supreme Court rules on public access to preliminary hearings in the Diaz litigation.
• 1992 (August 31): California Supreme Court affirms the Diaz convictions and death judgment.
• 1995 to 1996: Deaths and cardiac emergencies on a ward at a veterans hospital in Northampton, Massachusetts.
• 2000 to 2005: Niels Högel active at hospitals in Oldenburg and Delmenhorst.
• 2001 (March 14): Federal jury convicts Kristen Gilbert of four murders; she is sentenced to life without parole after the penalty jury declines death on March 26.
• 2002: Five elderly women collapse on orthopedic wards in Leeds; Ethel Hall’s blood is tested in November.
• 2002 to 2004: Killings of drivers in Delhi and neighboring states attributed to Devender Sharma’s gang.
• 2004: Sharma arrested in connection with a kidney racket and the killings.
• 2005 (June): Högel caught giving a patient an unprescribed drug.
• 2006 (May to September): Petr Zelenka gives patients a medicine no doctor ordered; the hospital ends his employment on September 25; he is arrested December 1.
• 2008 (February 21): Zelenka convicted of seven murders and ten attempted murders.
• 2008 (March 3): Colin Norris convicted by an 11 to 1 majority.
• 2015 (February 26): Högel sentenced to life.
• 2019 (June 6): Högel convicted of 85 murders.
• 2020 (July): Sharma re-arrested in Delhi after jumping parole.
• 2021 (February 12): Criminal Cases Review Commission refers the Norris case back to the Court of Appeal.
• 2022 (October 13): Högel’s former superiors acquitted.
• 2023 (May 24): Heather Pressdee arrested.
• 2024 (May 2): Pressdee pleads guilty and receives three consecutive life terms.
• 2025 (May 20 to 21): Sharma re-arrested in Dausa, Rajasthan.
• 2025 (June 26): Court of Appeal upholds all five Norris convictions.
• 2026 (March 17): Högel’s minimum term fixed at 28 years.