Sweden detained the Malta-flagged Vezhen after discovering damage to a fiber-optic cable between Sweden and Latvia on Jan. 26.
The incident was one of several involving damage to cables and other infrastructure in the Baltic Sea amid heightened tensions between the West and Russia over Moscow’s war in Ukraine.
"The investigation concerning a cable break between Sweden and Latvia in the Baltic Sea has clarified that it is not a case of gross sabotage," Swedish prosecutors said in a statement.
Prosecutors said they had decided to lift the seizure of the Vezhen, which was suspected of causing the damage.
"It has been established that a combination of weather conditions and deficiencies in equipment and seamanship contributed to the cable break," Senior Prosecutor Mats Ljungqvist said, adding that investigators confirmed Vezhen was responsible.
The damage to the cable, owned by Latvia's state radio and television center LVRTC, occurred in Swedish territorial waters at a depth of at least 50 meters (164 feet).
Alexander Kalchev, CEO of the ship's operator, Navigation Maritime Bulgare (Navibulgar), told AFP that Swedish authorities had officially informed the company that "there is no reason to believe that sabotage or malicious act was committed on board by our crew."
Kalchev said the crew was in "good health" and would resume their journey when ready.
The ship was transporting fertilizer from Ust-Luga, Russia, to South America when the incident occurred. Kalchev said an investigation found that one of the ship's anchors was damaged and had dropped into the sea, possibly dragging along the seafloor.
"The ship can continue to operate with this damage for the next three months, it has permission to do so, but we will try to stop in Denmark to repair the damage," he said Monday.
