The Zurich prosecutor’s office has opened a criminal investigation into suspected violation of anti-racism laws after a member of the rightwing Swiss People’s Party tweeted: “Maybe we need a new Kristallnacht … this time against the mosques”.

Also referred to as the Night of Broken Glass, Kristallnacht is the name given to a pogrom against Jews in Germany in November 1938, during which nearly 100 people were killed and businesses and synagogues attacked while authorities looked on.

In a statement on Tuesday, the prosecutor’s office said it had interviewed the author of the tweet, searched his home and seized the equipment used to post the comments on social networking site Twitter.

According to the prosecutor’s office, the author admitted to having written the tweet, but said it had been taken out of context by the media. The tweet was apparently made in response to the acquittal in May of a Muslim man who had said it was “OK” for a man to beat his wife if she refused to have sex with him.

Tweeted on Saturday, the author had removed the comments from his Twitter account and denied he written it. But the newspaper 20 Minuten on Tuesday revealed it had retrieved the tweet, along with another which said: “I would like to stand certain people up against the wall and shoot them. Less dirt on the earth would be good”.    

The author sits on the local school board and is a member of the executive committee of a local branch of the People’s Party in Zurich (districts 7/8).

In a statement, president of the city of Zurich People’s Party, Roger Liebi, said the comments were “unacceptable” and called for the man to be expelled from the party.

On Tuesday evening the local politician at the centre of the controversy anounced his immediate resignation from the party.

The move was welcomed by the party branch, whose president Urs Fehr said he deplored any form of incitement to violence against individuals or minorities.

The Young Greens called for the man to resign from his position on the school board and, along with the Islamic Central Council, is considering pressing charges.

The Swiss Federation of Jewish Communities said the tweet was offensive to Jews and Muslims and called on the Swiss People’s Party to condemn the comments as unacceptable.

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