Victory by Kulsoom Sharif, who is now receiving medical treatment in London, was declared by her daughter Sunday in front of supporters at the head office of Sharif's Pakistan Muslim League-Nawaz (PML-N) party in Lahore. In her absence, Maryam had run her mother's campaign.
This was the first time when former prime minister Muhammad Nawaz Sharif's daughter Maryam Nawaz appeared on the roads of the provincial capital to campaign for her mother Begum Kulsoom Nawaz.
"Nawaz Sharif has won" against the court decision disqualifying him, Maryam said.
Arrest warrants can be issued for former prime minister Nawaz Sharif and Finance Minister Ishaq Dar if the suspects continue to remain absent from NAB proceedings.
Kulsoom Nawaz stood in place of her husband Nawaz Sharif, who was disqualified from office in July over a corruption inquiry.
The official results of the by-election will be released later by the Election Commission of Pakistan. Sharif denies any wrongdoing.More news: Here's What Trump And Clinton Voters Watch
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The younger woman, who has been described as a future leader by political insiders in Pakistan, addressed jubilant workers from the PML-N party late Sunday evening.
At one side, there was the PML-N.
Pakistan Tehreek-e-Insaf, led by the cricketer-turned-politician Imran Khan, had hoped a victory would aid its yearslong anti-corruption crusade against the Sharif family.
Long queues formed outside polling stations in the city on Sunday morning. "You people have set a precedent for the coming generations that only a decision backed by the public is acceptable", she said.
"These results show that the voters, in general, have not accepted Sharif's contention that he had been ousted under an orchestrated conspiracy", Kamran Khan, a Karachi-based political analyst, said.
Milli Muslim League candidate came third with 4,174 votes, while Pakistan Peoples Party candidate got 2,520 votes. Sheikh, the MML candidate, was also named as by the United States as a "specially designated global terrorist" in 2012, for his alleged role in leading fundraising and operations for LeT.