There's a Swedish article about it on SVT, the Swedish national news media outlet. It's actually strangely long for being on SVT, I think there's some anti-competition laws that prevent them from doing journalism with too much detail.

I believe the original source is this article from Kontext Press.

Edit: I ought mention that I tried, but I struggled to find any articles about in English.

For some additional context though; the American organisation that tipped off the police here in Sweden was the NCMEC, the National Centre for Missing and Exploited Children.

The police examined the boyfriend whom they'd described as "not prepubescent", to ensure that he has the same birthmark that appeared in the pictures.

The prosecutor that signed off on the decision to raid this man's home, Titti Malmros has resigned.

Also this gem, which is from the Kontext Press article.

If a police officer commits misconduct while masked, how do you then investigate it?
Well, it's not really possible if one cannot establish who has done what, says prosecutor Lena Kastlund

Were all the officers present questioned?
No, they were not, because you cannot question them if you don't know who is suspected. You can't interrogate someone without informing them of the suspicion, and you can't question everyone who is suspected either. We have very high standards of evidence, so that no innocent person is suspected.

Can't they be heard as witnesses then?
Not if they later could become suspects.

Then is there any possibility of redress against officers who are masked?
There's always a possibility, but there may be difficulties. Plus, there are other officers present who may have heard things. We always try to do as much as possible.

Do you think that everything that could have been done has been done in this case?
Yes, that's my opinion at least. I stand by my decision and believe I've done what can be done.

I can't help but read this as; it's perfectly okay to break into a person's home in the middle of the night, assault them, and take them away from their home without informing them of where they're going or why, but you can't possibly accuse a police officer of misconduct; that requires a lot of proof which is magically unobtainable.