On 27 July 2013 Imtech announced that a criminalist officially named as "Mr. Y" had been consulted in 2011 to investigate the corruption in the reconstruction of the twin towers in Frankfurt. He identified more than he should; he warned the company in his final report in May 2011 about mafia structures and he charged the manager of the German subsidiary, Klaus Betz. Betz was covered by the company for two years. The investigator, identified by the Telegraaf as Thomas Wüppesahl, received a ban from Imtech 2011. When the corruption became known in spring 2013 the company lost a value of 1 billion Euros on the stock market.