The two minors will be prosecuted for aggravated defamation and could be ordered to pay out a total of 700,000 kronor ($104,000) in damages to victims, reported local newspaper Göteborgs-Posten (GP).
Within a couple of days, the girl received nearly 1,000 tips and by approving the entries she published the pictures of a large number of young girls and boys along with derogatory comments and alleged information about their sex lives.
The girl claimed she clicked "OK" on most of the posts, more or less in panic, reported GP. As a result, the pictures and comments could be viewed by any Instagram user.
As the information spread on social media, riots broke out at two high schools in Gothenburg - Plusgymnasiet and Framtidsgymnasiet. The crowds called for revenge on the persons behind the account, who were said to be pupils at the schools.
However, the prosecuted teenage girls do not attend either of the schools and are, in fact, not yet in high school.
The 16-year-old who has denied the charges made against her has been linked to the incidents partly through the 15-year-old's testimony and partly through sms-traffic indicating that she at least had good knowledge of the Instagram account.
"I will not say anything more except that my client denies the charges," said lawyer Claes Östlund.
"This is a sensitive case and I will hold off making any statements until the prosecutor has submitted the summons application," he added.
Once the preliminary investigation is made public the identities of those who submitted tips for the Instagram account could also be revealed and they may also face charges.