A large group of users are said to be women who check up on men they are dating, and representatives of the sites have said in interviews that they perform an important function in helping people avoid becoming victims of crime.
But SVT has identified ten cases in which convicted people have had their records erased after suing the databases. These include convictions for sexual assault of children, violation of women's privacy and assault.
A man convicted of seven counts of child sexual abuse sued one of the sites, which deleted all records of his crimes.
"We have received a deletion request and carried out the removal," the site's representative wrote in an email.
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