A threat letter sent to a committee investigating the crimes of National Socialist Underground (NSU) and a bullet left in the mailbox of a witness add to the murky developments in the case of the German neo-Nazi gang. The NSU is responsible for killing 10 people, including eight Turkish-Germans, in racially motivated murders between 2000 and 2007, as well as a bombing in a Turkish neighborhood and 15 bank robberies.

Wolfgang Drexler, who heads a committee of the Baden-Württemberg parliament, the state in which the NSU is accused of murdering a German policewoman, acknowledged that he received a threat addressed to him and the committee on Monday. He did not disclose any details about the letter, but said that there was also "a matter of security" related to a witness who was scheduled to testify and the committee delayed hearing the witness after the development to March 5. German media reported that the witness was Sven Rosemann, who used to run in Germany's neo-Nazi scene and who personally knew NSU members. A bullet was found in the mailbox of his residence.

The NSU's three members managed to dodge authorities for years before being captured in 2011, apparently by chance when police stumbled upon a video in which they boasted about their crimes. Beate Zschaepe, the only surviving member of the gang, is being prosecuted in the lengthy trial. Uwe Mundlos and Uwe Boehnhardt,the two other members, killed themselves when police closed in on them in 2011 after a botched robbery.

Blunders on the part of authorities investigating the NSU, or coincidences leading to destruction of critical evidence, had been piling up in the case since the gang's existence was made public in 2011. Critics of the case also claim police and intelligence services that hired people from the neo-Nazi scene as informants tried to erase their tracks leading to the NSU case.

Despite its links to many gangs in Germany's neo-Nazi scene, the NSU apparently went unnoticed for years from the late 1990s to 2011. Authorities initially blamed domestic disputes in the Turkish-German community for the murders and other crimes between 2000 and 2007. German media had dubbed the murders the "döner killings" in reference to the popular Turkish dish.