An investigation has been launched into how sacks containing some 400,000 euros went missing from an armored truck while it was aboard a ferry traveling from the mainland to the island of Thasos, harbor authorities said yesterday. The truck belonged to a security firm that was responsible for carrying 700,000 euros from Emporiki Bank in Kavala to a branch on Thasos. When the drivers arrived at the island bank, they opened the truck doors only to find that the sacks of cash had disappeared and just a metal safe containing 300,000 euros was left inside. The truck had boarded the Thasos 2 ferry from the port of Keramoti in northeastern Greece on Thursday morning. Police sources say that it is most likely that the money was stolen from the truck while it was on the ship. The security van driver, Dimitris Detsos, and his co-driver, Nikolaos Papaconstantinou, are due to be questioned by the Kavala harbor police. Emporiki Bank has also sent investigators to Thasos to make inquiries.