The Finland-Estonia undersea cable investigation has moved into a new phase after Finnish police formally arrested two crew members of the cargo ship Fitburg, which authorities suspect damaged an offshore telecommunications link on 31 December 2025 in the Gulf of Finland.
Finnish investigators have not disclosed the suspects’ nationalities or roles on board. Two other crew members have been placed under a travel ban, while the rest of the 14-person crew remains under scrutiny as authorities continue interviews and technical examinations.
How the Finland-Estonia undersea cable was damaged
The damaged link is an Elisa telecommunications cable running between Finland and Estonia across the Gulf of Finland. The disruption was discovered early on 31 December, and Finnish authorities moved quickly to identify a vessel operating near the break.
Finnish police are investigating the case as aggravated interference with telecommunications, aggravated damage, and attempted aggravated damage. Officials have stressed that the legal characterisation may change as the preliminary investigation progresses.
Alongside work on the ship itself, authorities have launched an underwater investigation around the broken cable. Finland’s Border Guard (Rajavartiolaitos) has supported the operation, and the patrol vessel Turva is coordinating operational work at the underwater scene in cooperation with the National Bureau of Investigation.
Why the Fitburg is under suspicion
The Fitburg, a 132-metre cargo vessel sailing under the flag of Saint Vincent and the Grenadines, was seized on 31 December and brought to Kantvik port in Kirkkonummi, west of Helsinki.
Investigators have said they are assessing the “course of events” and the “different roles” among crew members, based on interviews and investigative measures carried out on board. Detective Superintendent Risto Lohi of the National Bureau of Investigation (Keskusrikospoliisi, KRP) has described the crew as cooperative.
Finnish authorities have not presented public evidence that the cable break was intentional. Lohi has declined to speculate on whether the case could involve state-level hybrid influence, noting that the investigation is still at an early stage.
Arrests, travel bans, and what remains unclear
Under Finnish law, an arrest and a travel ban are procedural measures that allow investigators to secure a case while evidence is collected. In this investigation:
- Two crew members have been arrested.
- Two crew members are under travel bans.
- Police have not said whether the arrested individuals were officers or crew in operational roles.
Officials have also declined to comment on nationality details for the arrested individuals, even though authorities have said the crew includes citizens of Russia, Georgia, Azerbaijan and Kazakhstan.
At this stage, several key elements remain uncertain, including:
- the precise mechanism that damaged the cable;
- whether the break resulted from negligence, a navigational incident, or deliberate action;
- how responsibility is distributed within the ship’s chain of command.
Russia’s offer of “assistance” and Finland’s response
Finland’s Minister of Defence (Puolustusministeri) Antti Häkkänen has confirmed that Russia offered assistance to the ship’s Russian crew members.
Häkkänen told Finnish media that Moscow has made similar offers in past cases linked to suspected hybrid influencing. He said Finland would deal with the case “normally and calmly” and according to Finnish procedures.
Russian authorities have not publicly provided evidence about what happened to the cable. Finnish investigators have also avoided attributing responsibility to any state actor.
A wider Baltic Sea pattern of cable incidents
The Fitburg case comes after a series of undersea infrastructure incidents in the Baltic Sea region in recent years, including cable breaks and damage affecting energy and telecommunications links.
Finnish investigators have pointed to similarities with the Eagle S case on Christmas Day in 2024, while also stressing that each incident must be assessed on its own facts. In October, Helsinki District Court ruled it lacked jurisdiction to hear charges against officers linked to the Eagle S incident.
The recurring nature of these events has increased political sensitivity in the region, where Baltic Sea states and NATO members have repeatedly warned about the need to protect critical underwater infrastructure.
Sanctioned steel cargo adds a separate investigation track
Finnish Customs (Tulli) has said the Fitburg was carrying steel products originating in Russia that experts assessed as falling under EU sectoral sanctions.
Customs detained the cargo to verify compliance with EU import requirements and carried out an inspection of the vessel on 31 December. The cargo remains detained while authorities assess how EU sanctions legislation applies.
This sanctions-related issue is legally distinct from the cable investigation, but it adds another layer of scrutiny for the ship’s operator and could lead to separate proceedings.
What happens next
Finnish police say interviews and technical investigations will continue. The National Bureau of Investigation has also established a Joint Investigation Team (JIT) with Estonia, aimed at enabling closer cross-border cooperation.
In the coming days, investigators are expected to focus on the underwater site examination, ship logs and equipment checks, and the chain of decisions on board during the ship’s transit through the Gulf of Finland.
For Finland and Estonia, the case is also a test of resilience: not only the ability to restore a damaged telecoms link, but also the capacity to investigate complex incidents in a sea lane that has become increasingly central to Nordic and Baltic security.
