The two sexual crimes are said to have taken place in the Luleå-Boden police area.
In one case, a lone perpetrator is suspected of raping an adult woman.
The crime must have taken place outdoors and a man has been arrested in the case.
Serious rape
In the second case, four people have been arrested on suspicion of aggravated rape of an adult woman.
The police are currently working on various investigative measures such as technical evidence and interrogation.
In both cases, the prosecutor will decide whether the men should be arrested.
The police initially see no connection between the two rapes.