In most of Israel, the local elections held a week-and-a-half ago were uneventful. But in the city of Beit Shemesh, they sparked an angry reaction that is growing by the day.

On Tuesday, hundreds of residents held a demonstration demanding an investigation into alleged voter fraud and that the Charedi victory be overturned if the probe reveals wrongdoing.

“This wasn’t a democratic election and we can’t accept the results as fair,” said Nili Philip, a demonstrator who is collecting testimonies supporting the claim of fraud.

Hodaya Epstein, a member of the demonstration’s organising committee, said: “As a citizen I fee that if we want this state to be democratic we have to show that the rules of democracy can’t be broken.”

The election campaign was a sectarian affair, pitting Charedim against most other residents. Supporters of the incumbent mayor, Moshe Abutbul, who belongs to the Orthodox Shas party, presented challenger Eli Cohen as an enemy of Judaism. They claimed that it was a religious obligation to keep him out of power, and even invoked Holocaust imagery to underscore the dangers that he supposedly posed.

“The atmosphere of the election campaign really left a bitter feeling,” said Catriel Lev, a modern-Orthodox resident. “You can say that your candidate is good without saying the other side is practically the devil.”

Beit Shemesh is bitterly divided at the best of times. It is the city that became the focus of the international media two years ago when an eight-year-old girl was spat on by religious zealots on her way to school.

To the fury of non-Charedi residents, signs hang in some shopping areas demanding modest dress, and there have been cases of self-appointed modesty patrols trying to enforce the order.

But, as if the highly charged electoral campaign was not enough to turn up the heat, then came the results, and the scandal. Mr Abutbul won the election by under 1,000 votes — and his opponents claim that a thorough probing of irregularities could change the result.

They are in the process of petitioning national authorities for an investigation.

Police raided a flat in the city on election day and found 200 identity cards, which raised suspicion that they were intended for voter fraud.

Mr Abutbul’s opponents are arguing that the several hundred disqualified votes were intentionally sabotaged. They are also claiming that people showed up to vote to find that their ballot had been used.

“There are all these weird situations that don’t really make any sense,” said Ms Epstein.

Calls and emails requesting comment for this article from Mr Abutbul’s office were not returned. In the Israeli media, Mr Abutbul was quoted calling on his opponents to respect the “rules of democracy”.

Some non-Charedi residents of Beit Shemesh, instead of fighting the latest election result, are looking ahead to the next local elections in five years, and proposing that sectarian tensions are ended by splitting the city into two.