The detention of the man is related to the Neo Nazi violent riot led by the Finnish Resistance Movement in Jyväskylä on August 1.
The man who gave up himself to the police over the weekend has a background of several previous convictions.
The man has previously been convicted of, among other crimes, assaults and smuggling after he attempted to import illegally 18 pieces of gas sprays.
Five Finns and two Swedes were previously remanded in connection with the Jyväskylä riot.
One of the Swedes in custody has contested his remand at the Vaasa Court of Appeal.
The Court of Appeal will hear the case on Wednesday.
The police are still looking for several people for interrogation in connection with the riot.
