Six men, all in their 20s, were arrested after the attack, and one was soon released. The remaining five remained in police custody until they were released on Wednesday. The investigation is still ongoing.
The Expressen newspaper reported that the suspects are all asylum seekers and that the rape allegedly took place at asylum accommodation.
Radio Nordfront released a video that shows a member of the Nordic Resistance confronting the rapists.
The Swedish man in the video has since been arrested for the confrontation.
Visby has seen several protests held to support the raped woman and condemn the release of the perpetrators.
On Wednesday, about 100 people walked from the local police station to the place where the rape had taken place, Expressen newspaper reported. Also on Wednesday, a crowd of protesters attacked the local asylum accommodation with stones. It is not clear whether it is the only migrant facility in the town.
A similar protest took place on Friday. These events prompted Swedish authorities to send extra police to the town, and some 60 officers arrived in Visby on Friday to stabilize the situation.