The German police hired a company to create a trojan which aimed to gain access to users who use the Skype messenger, which was known at the time to be inaccessible to foreign parties due to the encryption and decentralized structure.
The aim was to undermine the citizens secure communication capabilities.
archived source: https://wellthissucks.xyz/2008/01/28/german-police-paid-for-trojan-to-access-skype-user-communication-archived-source/