The rape is alleged to have occurred when the artists performed at a school dance at a town in central Sweden. Police monitoring the event arrested the men, 21 and 29-years-old, late on Saturday night following a report from the girl.
The 21-year-old is suspected of rape and the 29-year-old of sexual coercion, police confirmed to news agency TT. Police were unable to confirm any further details of the case so as not to compromise their investigation.
The 29-year-old was released from police custody at around 3am on Sunday morning. The 21-year-old was released shortly after 6.30pm, following a decision by the prosecutor. Suspicions against the men remain but they were considered to no longer affect the investigation.
The 21-year-old artist and the 15-year-old girl both underwent a medical examination during the night.
The alleged victim of the rape reported the incident to police attending the concert in an official capacity.