The answers to what actually happened to the poisoned family in Söderhamn have been few – until now.
It was after intensive detective work with experts abroad that doctors in Sweden were able to crack the code.
– I have worked with poisoning cases for over 40 years and I have never come across a case like this before, says Kai Knudsen, chief physician and poisoning expert to TV4 Nyheterna.
Prosecutor Christer Sammens confirmed on Tuesday that the family of two in Söderhamn had been poisoned by the extremely toxic substance phosphine. A four-year-old girl in the family died and the remaining family members received intensive care.
By looking at high-profile deaths abroad, it was finally concluded that it was phosphine that took the girl’s life.
The chief doctor: “Extremely unusual”
TV4 Nyheterna met Kai Knudsen, chief physician and poisoning expert at Sahlgrenska University Hospital in Gothenburg, who came to Hudiksvall Hospital in October 2023 to work as an intensive care physician in the case.
The group of doctors in which he worked tried to help the police in their work to solve the mystery of what poisoned the family.
– This has been a mysterious case. Difficult in many ways. Above all, extremely unusual, says the chief physician.
So the poisoning mystery was solved
A list of over 200 substances was checked off in the effort to crack the code on the poisoning. Together with experts in Great Britain and the United States, everything was done to find out the answer.
– There has been no direct analysis method for this. But you have had to set up an analysis method to be able to see if it was this thing called phosphine.
In the quest to solve the mystery, researchers together with the police also began to look at investigations of similar cases.
– People who can get hold of it in that way, especially in Asia and the Middle East, where it has happened several times that it has occurred in terms of suicide and murder, says Kai Knudsen and continues:
– In London there was a case where the gas went into the neighbor and an 11-year-old girl died. Then you don’t know if there was an intention or if it was an accident.
The theory: Poisoned at home
The 2021 case in London where a woman used phosphine to control bed bugs is now suspected of manslaughter.
Prosecutor Christer Sammens believes that the family in Söderhamn has been poisoned at home. However, it has not been possible to find any packaging linked to the extremely toxic substance.
The preliminary investigation into murder is still ongoing. The criminal classification may change.
The scientists who finally found out which poison it was were satisfied that they were able to solve the mystery.
– We really want to try to solve this because it has been so confusing. As I said, this type of poisoning is extremely rare in Sweden, says Kai Knudsen.