French authorities have taken into custody the Russian captain of a seized oil tanker believed to be part of Moscow's shadow fleet, a prosecutor said on Wednesday. The French navy detained the Tagor on Sunday in international waters with the help of Britain on suspicion the ship was flying a false flag after its captain refused to comply with orders. The captain was arrested on Tuesday and faces up to one year in prison and a 150,000-euro ($174,000) fine, said the prosecutor in the northwestern city of Brest, Stéphane Kellenberger. The shipowner, currently being identified, may be subject to the same penalties, he added. Read moreFrance backed by Britain intercepts sanctioned oil tanker sailing from Russia The Tagor is suspected of carrying Russian or Iranian oil despite international sanctions, and is linked to petroleum shipping magnate Mohammad Hossein Shamkhani, according to open-source database Opensanctions.org. Shamkhani is the son of security official Ali Shamkhani, who was an adviser to the former Iranian supreme leader Ali Khamenei, both of whom were killed on February 28, the first day of the US-Israeli attacks that started the Middle East war. According to French authorities, the Tagor was on its way from Murmansk in northwestern Russia when it was boarded. It was falsely flying a Cameroonian flag and was heading toward Limbe, a seaside city in the west of the African country, they added. (FRANCE 24 with AFP)