A Czech court on Tuesday dropped charges against American Ronald Adams, the former chief executive of the Czech truckmaker Tatra who was accused of graft over a defence contract. The court in the eastern city of Brnso \"can only rely on the evidence presented and it proved insufficient,\" judge Sarka Dufkova said. The case involved a 2008-2009 military contract for 588 Tatra trucks valued at 2.7 billion koruna (105 million euros, $140 million). Adams was charged last year after former Czech defence minister Martin Bartak accused him of offering him a 20-million koruna bribe in return for the military increasing its order. Dufkova said the men met briefly in 2009 on the sidelines of an international trade fair, but Adams said they only shook hands and exchanged small talk. He retired from the company in July and denies the allegations. Bartak himself was accused of attempted corruption over the same contract by former US ambassador to Prague William J. Cabaniss in 2010. Corruption is a persistent problem in the Czech Republic, whose government fell over a spy and bribery scandal this year. The EU member ranked behind countries like Costa Rica and Rwanda in Transparency International\'s 2012 Corruption Perception Index. A travel agency in the capital Prague offers tours highlighting sites linked to the corruption that has plagued the ex-communist nation for decades.