The FBI developed the encrypted service "Anom" which was then spread to criminal networks.
Thanks to the operation, which was named "Trojan Shield", around 800 people have been arrested around the world in recent days.
On Monday morning, an attack took place in Linköping at central addresses with connections to the operation.
Three people have now been arrested in the case, suspected of a serious drug offense.
Two were arrested
On Tuesday, a man in his 50s was arrested on suspicion of a serious drug offense.
The man has not previously been convicted of a crime that can be linked to organized crime.
A woman in her 30s who was previously unpunished was also arrested on the same grounds.
Another person is a suspect in the case, but who it is is currently covered by confidentiality in court.