There's a precedent and it isn't helping the chances for a conviction:

This is the second undersea cable-related investigation to reach prosecution, as another Russian-linked ship, the Eagle S oil tanker, was involved in another suspected sabotage on Christmas Day 2024. Three officers of the “shadow fleet” tanker were charged with the same criminal cases that the Fitburg crew are facing, although Finland failed to secure a conviction, as the court said that it did not have jurisdiction over the case because the incident happened outside of Finnish territorial waters. The ruling is currently under appeal, though, with prosecutors arguing that “the effects of the crime materialized here in Finland.”