1986 Zurich shooting

On 16 April 1986, Günther Tschanun, chief of the Zürich building authority (Amtshaus IV), opened fire on colleagues at his workplace using a Taurus Model .38 Special revolver, killing four people and seriously injuring one. The Tages-Anzeiger described the attack as "one of the worst crimes in post-war Swiss history." Tschanun reportedly intended to kill himself during the attack but was unable to do so, and instead fled the scene.

The shooting followed a period of tension within the department Tschanun headed. Days before the attack, an article critical of his management practices was published in the Züri-Woche, and shortly afterward two officials wrote to their superior criticizing Tschanun and calling for his dismissal. The day before the shooting, Tschanun wrote a will, leaving furniture to his girlfriend and the rest of his estate to his wife. He later claimed he felt he had "no choice" and had been "bullied," and said he had originally bought the gun out of fear of his girlfriend's husband.

After the shooting, Swiss authorities issued a 10,000-franc reward for his capture. Tschanun evaded arrest for about three weeks before being caught in France.

In 1988, the Zürcher Obergericht sentenced Tschanun to 17 years in prison on four counts of intentional homicide. The federal prosecutor sought a murder conviction instead and appealed to the Federal Supreme Court of Switzerland. In January 1990, that court overturned the original sentence, convicting Tschanun of murder and imposing a 20-year sentence. At the time, some figures on the Swiss political left were accused of downplaying the crime by characterizing Tschanun as a "victim of the capitalist system" under excessive pressure.

Prison authorities reportedly did not trust Tschanun, but he was released on parole in 2000 for good behavior. He was given a new legal identity, Claudio Trentinaglia, and relocated to Ticino. He died on 25 February 2015 in a bicycle accident, falling down the bank of the Maggia river; not wearing a helmet, he struck his head and died. His neighbors were unaware of his true identity, and his past was not publicly disclosed at the time of his death. The connection became public only years later after journalist Michèle Binswanger requested his case file.

The case has since been revisited in other media, including a 2016 book by Nicolas Lindt, a 2010 film described as inspired by the case, and a 2023 docufiction film retelling events from a neighbor's perspective.