[aqsalose]

Depends on the crime. For serious crimes I think it is quite common?

Like, Finnish law claims jurisdiction over all crimes committed against or by Finnish citizens committed abroad, no matter the location or acts legality per local law, if the crime could result in prison term of 6 months or longer according to the criminal code of Finland. We also claim jurisdiction over some particularly heinous crimes committed abroad no matter the nationality of victim or perpetrator. I think it is very rare to see it applied, because crimes according to Finnish law are often crimes abroad, too (I mean, the location of country often takes precedence?). And I don't think our laws grant our authorities power to act outside territory of Finland (like the US sometimes does).

But if a Finnish citizen traveled to country X, did something bad enough to mandate a long prison sentence, came back to Finland, was found, and for one reason or other were not extradited back to X for trial there, they would be tried here.