These are so-called "Ghost telephones", heavily encrypted telephones that criminals use to communicate.

Several of these have been sent to the US FBI, which has now managed to get into them.

Deputy Chief Prosecutor Anna Svedin leads the Adriana investigation and led the investigation into the artist who is suspected of having used illegal weapons in a music video.

One of these weapons is then said to have been used in the murder of twelve-year-old Adriana in Botkyrka outside Stockholm in August last year.

In September, the artist and two other men were sentenced to long prison terms for serious gun crime.

The same video features a Ghost phone.

Ted Asplund, at the National Operations Division of the Police (NOA), is positive about the FBI's progress.

"Assuming that the FBI has a method for unlocking the units, the prospect is good that this knowledge will be spread to Swedish IT forensics so that in the long run we can handle this ourselves," he tells SvD.

Since the police, in France and elsewhere, cracked the encryption services Encrochat, Sky and Anom, numerous crimes have been solved, also in Sweden.

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Hear Judge Robert Schött talk about the importance of the music video for the verdict.

Photo: Police preliminary investigation / Kovan Alshawish / SVT