Russian forces lead a suspected hijacker of the Arctic Sea ashore from their warship at the Cape Verde island of Sal in August

Captain Ivan Boyko is baffled. “The authorities aren’t telling us anything,” says the deputy head of Solchart Arkhangelsk, an offshoot of the Russian-controlled Finnish company that operates the Arctic Sea, a cargo ship that went missing off Portugal two months ago. “Nothing like this has ever happened in living memory.”

Secrecy still surrounds the ship nearly seven weeks since the Russian navy intercepted it and arrested eight men, claiming it had foiled an act of piracy. Four of the crew remain on board under heavy military guard, with the ship still at sea after being refused entry to the Canary Islands port of Las Palmas.