The largest European hacker club, "Chaos Computer Club" (CCC), has reverse engineered and analyzed a "lawful interception" malware program used by German police forces. It has been found in the wild and submitted to the CCC anonymously. The malware can not only siphon away intimate data but also offers a remote control or backdoor functionality for uploading and executing arbitrary other programs. Significant design and implementation flaws make all of the functionality available to anyone on the internet.
http://www.ccc.de/en/updates/2011/staatstrojaner