Police have detained nine people, including the director of a state museum, from which at least two pieces from the treasure of King Croesus had been stolen and replaced with fakes, authorities said Monday. The treasure - a coin as well as Croesus' golden broach, in the shape of a winged seahorse - had been switched with replicas at the Usak Museum, in western Turkey, according to Tourism Minister Atilla Koc. The pieces were taken once before in the 1960s and displayed at the Metropolitan Museum in New York before being returned to Turkey in 1993. Investigators said in a report that the recent theft probably occurred between March and August 2005, and that the switch could not have been carried out "without the knowledge of museum authorities," daily Milliyet reported Sunday. Usak Gov. Kayhan Kavas said Monday that police had detained nine suspects, including Usak Museum's director, Kazim Akbiyikoglu. Prosecutors have been investigating the theft since December, when authorities received an anonymous letter about the theft. The treasures spent three years in a museum in Ankara before ending up back in Usak. One object - a golden bird figure - was stolen during the return, Milliyet said. Croesus was king of the Lydians in the 6th century B.C., and was the richest man of his time in what is now western Turkey. His name has become synonymous with great wealth, as in the phrase, "as rich as Croesus."