"We will look closer at the Instagram account and find out if the person is guilty of slander," Gothenburg police duty officer Lena Matthijs said.
The police would not confirm if they had spoken with the 17-year-old girl believed to have started the account.
"Whom we speak to is part of our investigation and we cannot talk about it," she said.
The call for "Gothenburg sluts" saw hundreds of pictures of girls and boys uploaded to Instagram. They gave names and alleged sexual activities of the teenagers portrayed in the pictures.
A backlash on Facebook saw teenagers talking about going to the school of the alleged Instagram user and beat her up.
The police downplayed that there had been any real threat of danger.
"A lot of people were there because big crowds are exciting. It would have been exciting for us when we were young, but social media makes it easier and quicker to assemble people," Matthijs said.
"I'd say 15 to 20 of the 150 teenagers were there specifically to cause trouble."