Published in “The Stentor” last Saturday, auto-translated from the original Dutch by Google Translate. This is the raw version. Corrections still to be made!

Richard Gill has already released two medical serial killers, including Lucia de Berk, by refuting statistical evidence. © Rob Voss

This Apeldoorn scientist saves innocent sisters from prison: Unfortunately, people do not want to believe in coincidence

Scientist Richard Gill from Apeldoorn helped ensure that Lucia de Berk was acquitted. He achieved the same in a similar case in Italy and now he is going for the hat trick in England. What drives him? 

Anne Boer 28-05-22, 08:00

Pure scientific curiosity is what drives him, says the internationally renowned mathematician Richard Gill from Apeldoorn. As an expert in statistics, Gill (70) worked for the Public Prosecution Service and the International Criminal Court. He has been retired for almost six years and is known as emeritus professor of statistics at Leiden University.

With his knowledge of the use of statistics, he was able to prove the innocence of two nurses who were convicted of serial murders from his office: the Dutch Lucia de Berk and the Italian Daniela Poggiali. Now he is campaigning for the release of nurse Ben Geen from England.

Sheer nonsense

All three are said to have killed patients on the job . Lucia de Berk was even convicted of seven murders. The burden of proof was mainly based on statistics. If Lucia worked, more patients would die than during her colleagues ‘ shifts. It turned out to be sheer nonsense, as Gill puts it delicately. “A matter of gossip and backbiting, looking for a scapegoat to save the hospital’s reputation and assumptions when no murder was committed at all. †


Unfortunately, people do not want to believe in coincidence, we want to have a cause. That’s why we also believe in devils and gods

Statistical evidence plays a major role in research, including serial killers in the medical world. ,,But then you have to interpret the figures properly ” , says Gill. “If apparently many people die in a hospital, you first have to look closely at the cause. Are there perhaps more patients than usual ? Are they sicker than in other periods? Has the registration method been adjusted? Are there changes in the staff? If you immediately look at which nurse was present, you also skip the most important questions: is it murder or is it medical failure or even natural death? †

According to Gill, that immediately touches on another sore point. “A hospital is a place where people die, but often the cause of death is not clear. This can lead to clusters of suspicious deaths. You have to know which deaths you count, otherwise the police will look for evidence for claims. †


According to Gill, you should always keep in mind that there can be a good, innocent reason for an event. “Look at how often someone works. Full-time nurses experience more deaths than part-time nurses. If someone works full-time and is passionate about their craft, they’re even more likely to be there when someone dies than someone who works a few days a week or works strictly within the schedule. †

Scientist Richard Gill. © Rob Voss

According to him, you should never rule out a strange combination of circumstances. “They happen, even without murder. A famous example is an American couple who won the top prize in two different lotteries in one day . What are the chances of something like this happening? It really happened. Unfortunately, people do not want to believe in coincidence, we want to have a cause and look for a scapegoat. That is why we also believe in devils and gods. †


Richard Gill was born in England. His father was also a scientist. Love brought him to the Netherlands in 1974 at the age of 23. Six years earlier, on holiday, he had fallen head over heels for a daughter of a Dutch friend of his father’s. Both fathers work for Wavin from Hardenberg. After some wanderings, Gill ends up in Apeldoorn in the early 1980s, never to leave. He lives in an old mansion, in a sea of lush greenery. This was his wife’s childhood home. To keep his head above water financially, he works extra hard to make a quick career .

The medical world crosses his path early on. After studying mathematics at Cambridge, he obtained his doctorate for research into the question of how long cancer patients survive with a particular treatment. His calculation method turned out to be a godsend and is now also being applied in other areas. “It just happened to be on my plate. I didn’t have a topic and my promoter took this topic out of his drawer. It has had a lot of impact and the method is still widely used. †

witch hunt

His wife, who is a historian, points him at an early stage to the case of Lucia de Berk, who would later be convicted of seven murders in a hospital. “She spoke of a witch hunt and wanted me to watch it, especially when it became a witch trial, as she called it. She pointed out to me that statistics were used as evidence and so I should have something to say about it. I did not want to. Experienced statisticians were already involved, including people I knew. †

Lucia de Berk reacts happy after her acquittal © anp

When a book about this case was published in 2006, Gill took the plunge. “I was referred to the book by a colleague. I really didn’t know what I was reading, I was really blown away by it. It was crystal clear to me that the verdict was wrong and that the judges had misinterpreted the figures . †

The rest is history. Gill helped show that the figures failed to substantiate the accusation and Lucia was fully acquitted in 2010 after 6.5 years of wrongful imprisonment.


reads about a similar situation in Italy in 2014 , he immediately decides to jump back into action. This time, a nurse (Daniela Poggiali) is suspected of sixty murders. Gill calls his colleague Julia Mortera from Roma Tre University and together they offer their help. With success, this nurse has also been free since October after a previous sentence to life imprisonment.

Statistics is the science and technology of collecting, processing, interpreting and presenting data. Statistical methods are used to convert large amounts of data – for example about people’s purchasing behaviour, the housing market or the number of deaths in care – into useful information .

,,The statistics in this case were completely amateurish, it was not good. Prosecutors claimed there were more deaths when Daniela worked. Until she was arrested: then it suddenly dropped. We found that the death rate for all staff was high. Daniela was often present before the start of her scheduled shift and often continued to help after her shift was over. As a result, she was more often present when a patient died . It is easy to explain that the number of deaths decreased after Daniela was arrested. The news about the ‘ murder sister ‘ was widely covered in the media. As a result, the hospital attracted fewer patients . Fewer patients also means fewer deaths. †

Difficult bone

Gill is now investigating the serious allegations against English nurse Ben Geen. This is done at the request of his lawyer. It is still a very difficult task, especially because the legal system in England is different. Once again, Gill is convinced that the suspect committed no murders and that justice must prevail.

He has learned important lessons from these cases that he wants to pass on to everyone involved in the justice system worldwide, from lawyers to judges and from prosecutors to jurors. Together with other experts, he is writing a manual on how to use statistics in court, especially in criminal proceedings against so-called serial killers in healthcare. This is done under the supervision of the authoritative Royal Statistical Society. The book is due out later this year.


You can assume that a dog has four legs, but not everything with four legs is a dog. If Lucia had been looked at that way, she would never have been judged

Richard Gill

The message he has is basically simple: do not use statistical data until you have ensured that they are correct and use them well. “Name all the factors. Don’t jump to conclusions too quickly. Ask independent experts for help. Explore all possibilities. ” According to Gill, not only expertise from professionals is needed, but also that judges and lawyers are trained in a good interpretation of statistics.

Four legs

He gives a simple example. “You can assume that a dog has four legs, but not that everything with four legs is a dog. You can assume that someone from Peru speaks Spanish, but not everyone who speaks Spanish is from Peru. If Lucia had been looked at that way, she would never have been convicted. †

Typically, Gill finds that the suspects he helped are all striking people. They worked hard, had strong opinions, probably offended executives as a result, and ended up as scapegoats. “It really struck me how much they have in common. Ben Geen wanted to be an army doctor and was very passionate about his work. He saw his work as more than a job and did a lot extra when he could. He also clashed with managers because the hospital was constantly running into limits. †

criminal court

As an expert in statistics, Gill also worked for the Public Prosecution Service (Tamara Wolvers murder case) and the International Criminal Court (Lebanon Presidential assassination attempt). He has now been retired for almost six years, but he has no time to get bored. There is still work on his plate for years to come. Puzzles he likes to help solve. 

In addition, there are many subjects that he would like to delve into, such as the controversial Deventer murder case, which has intrigued him immensely for years. “I still think it possible that the convicted Ernest Louwes is innocent. I find the DNA traces on the murdered widow’s blouse particularly interesting. DNA is also statistical evidence and statistics tells us how to deal with uncertainties. There are now new molecular biological methods to get much more out of a track. †


Gill helps MP Pieter Omtzigt with analyzing data about custodial placements as a result of the benefits scandal. ,,We make a timeline to get a picture of cause and effect. So I don’t really have time to get any more nurses out of prison , ” he says with a smile.

Member of Parliament Pieter Omtzigt. © ANP

If a case of an alleged murder sister comes his way, he will probably have a hard time saying ‘ no ‘ . He enjoys puzzling and wants to prevent life from getting boring. The text on the back of his sweater might speak volumes in that regard: ‘ Keep calm, and this grandpa will solve it ‘ . Because yes. Gill, a father of three, is a grandfather and his five grandchildren like to stay with him and his wife in Apeldoorn.


He has to solve one of the many puzzles that has occupied him for years and sometimes even wakes him up: the case of Jos é Booij, who was confronted eighteen years ago with the custodial placement of her six-week-old baby Julia-Lynn.

“An unbelievable and horrifying story. She was crushed by the system and completely destroyed by it. I have lost contact with José , but I still have a box with her personal items, such as children’s drawings, diplomas , diaries and newspaper clippings about her fight for her child up to the highest courts in the Netherlands and Europe. . Julia-Lynn may be living under a different name now and may not even know her birth name. I want her to know who her mother is. That he never gave up. She is entitled to that. I hope one day to find her and give her mother’s things. And you know, this woman is also a special person, different from others. †

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