2002 Überlingen mid-air collision

On the night of 1 July 2002, Bashkirian Airlines Flight 2937, a Tupolev Tu-154 passenger jet, and DHL Flight 611, a Boeing 757 cargo jet, collided in midair over Überlingen, a southern German town on Lake Constance, near the Swiss border. All 69 passengers and crew aboard the Tupolev and both crew members of the Boeing were killed.The official investigation by the German Federal Bureau of Aircraft Accident Investigation,, identified as the main cause of the collision a number of shortcomings on the part of the Swiss air traffic controller service in charge of the sector involved, as well as ambiguities in the procedures regarding the use of the traffic collision avoidance system on-board.: 110 A year and a half after the crash, on 24 February 2004, Peter Nielsen, the ATC on duty at the time of the collision, was murdered in an apparent act of revenge by Vitaly Kaloyev, a Russian citizen whose wife and two children had been killed in the accident.

Source: Wikipedia