The previous arrest, in June 2011, occurred after police identified a 36-year-old man from the Stockholm suburb of Täby, who was committed to a psychiatric ward after being convicted of child rape, child sexual abuse, and aggravated child pornography offences.
“We found in his material a load of chat conversations. I have extracted a number of these that both shared and received child porn files,” said Henrik Westerberg of the local police to TT news agency.
Westerberg used the chat history to form a list of 60 potential suspects, 20 of whom were traceable residents of Sweden.
Of these 20, three were already known to police from previous arrests. The remaining 17 were all men, with no known connection to one another.
The police began questioning the suspects on Tuesday, and some offenders have already been released, though they are still under suspicion. One man has been detained.
“We are really pleased to get confirmation that our work in tracking these people has been worthwhile,” said Westerberg, who spent several months tracing the suspects through the previously seized material.
Almost 20,000 child porn images and 127 films were seized from the 36-year-old’s home in June.
An earlier raid on the man’s home had uncovered almost 7,000 pictures and 171 films. Several of the films showed young children and were “especially ruthless”, according to police.
The man confessed to aggravated child pornography.