While the BJP demanded that the polls in the Raja Rajeshwari Nagar constituency are countermanded, the Congress alleged that the apartment belonged to a BJP leader.
Nearly 10,000 "fake" voter I-cards were recovered from a flat in a constituency in Karnataka, setting off a war of words between the Congress and the Bharatiya Janata Party, which demanded countermanding of the poll for the seat, claiming the Congress was behind the racket, a charge the latter dismissed as a "lie".
The row erupted just three days before the keenly fought elections, with the two major contenders for power claiming the flat belonged to a woman associated with the rival party.
The Chief Electoral Officer of Karnataka Sanjiv Kumar, however, told the media the I-cards recovered from a flat in Rajarajeshwari Nagar constituency looked genuine but a deputy election commissioner rank official was rushing from the national capital to Bengaluru for a probe.
"It was earlier suggested that somebody was trying to break into our (computer) system to prepare fake ID cards.... that is not so," he said, adding it was for the Election Commission to take a decision on countermanding the election.
Prime Minister Narendra Modi, who was campaigning in Karnataka, attacked the Congress for adopting such tactics to win the elections.
"Thousands of voter ID cards were seized, 1 lakh voters slips were seized in just one place. They must have planned such games in 40-50 constituencies. You (voters) be alert. Such sin cannot be allowed during the celebration of democracy (polls)," he told elections rallies.
Addressing a press conference in Bengaluru, Union minister Prakash Javadekar claimed Congress candidate and the sitting RR Nagar MLA Munirathna Naidu was behind the alleged racket, which was exposed by BJP worker Rakesh.
Congress spokesman Rajdeep Singh Surjawala hit right back, alleging that flat owner Manjula Nanjamari and Rakesh, who was dubbed by Javadekar as the "whistleblower" in the matter, had BJP connections and both had contested the Bengaluru Municipal Corporation elections on saffron party tickets.
"This is the philosophy of the Congress....if voters do not vote for you, create fake voters," Javadekar said, claiming a "fake voter ID printing factory" was being run in Manjula's flat. Manjula, he said, was once associated with the BJP but was now with the Congress, and demanded her immediate arrest.
He alleged she had campaigned for Munirathna Naidu in the last assembly polls.
The Congress launched a counteroffensive, claiming the BJP was making such allegations because it was aware of its imminent defeat.
"They are making such allegations because of their imminent defeat, and after their workers and leaders were caught red-handed influencing voters in collating and collecting fake ID cards in order to influence the results of
the elections," Surjewala told reporters in Bengaluru.
"Javadekar runs a factory of lies. Rakesh was a tenant of flat No. 115 and it is mentioned in the list of BJP candidates who contested the corporation elections. Manjula is a former BJP corporator from Jalahalli," he said, citing newspaper reports.
While some TV news channels claimed Rakesh was Manjula's son, and others said she was his adoptive mother, the women at the centre of the controversy insisted they were relatives but maintained "no contact".
She told TV channels in Kannada, which was translated into English, that since she owned the land on which the apartment building stood, she had entered into a joint venture with a builder.
Manjula said she had rented or leased out the flats. The flat under question was given on rent to a woman named Rekha Ranjan and not Rakesh for office-cum-residence.
When asked whether Rakesh was her son or adopted son, she said he was a nephew and that they had "no contact due to strain in family ties".
Both the Congress and the BJP rushed to the Election Commission, making allegations against each other and demanding action.
A Congress delegation led by senior party leader Anand Sharma met the EC officials in New Delhi and alleged that the BJP was indulging in electoral malpractices.
While talking to reporters later, he accused the BJP of trying to "subvert the process of free and fair elections", and called the entire episode of seizure of voter I-cards "stage-managed".
He claimed Manjula was associated with the BJP and her "son" Rakesh had contested the municipal corporation election on a BJP ticket.
"The Election Commission must take action, and a police case be registered," he told reporters in New Delhi, adding the BJP was up to such tactics as defeat was staring it in the face.
A BJP delegation comprising several Union ministers met the poll panel hours later and petitioned it to countermand the poll.
"Top leaders of the BJP have requested the Election Commission to countermand the election to restore voter confidence. We also asked it to take note of the investigation done by TV channels.
"They (Congress) were doing economic profiling of voters to financially induce them to vote for the party...It may have happened in other seats too. A detailed inquiry should be made," Information and Broadcasting Minister Smriti Irani told reporters.
Karnataka polls: Everything you need to know
In Badami, it's advantage Siddaramaiah
Why Modi didn't visit Udupi's Krishna temple
Will Deve Gowda's citadel fall this time?