Lee Jae-myung, who was selected as the ruling Democratic Party‘s presidential candidate, now faces several challenges in the race for the top job, from clarifying property speculations and bringing together scattered party supporters.

Gyeonggi Province Gov. Lee on Sunday won the majority of the Democratic Party’s primaries, crushing his rival Lee Nak-yon, a former prime minister.

He won 50.29 percent of the votes and the narrow win was a surprise for Gov. Lee, who had won a solid majority in most regional primaries.

Lee said in an interview that “fake news” related to the Daejang-dong scandal could have affected the results, and sees it as a sign for him to work harder.

Over the past weeks, Lee has been mired in allegations related to a controversial housing development project in Daejang-dong that he promoted when he was reelected as Seongnam Mayor in 2014.

The controversy centers on Hwacheon Daeyu, a dubious company that participated in the project with a 1 percent stake. A former reporter, Kim Man-bae, who interviewed Lee before the project started, founded Hwacheon Daeyu, a week before a private-sector tender for the project began. Hwacheon Daeyu was able to earn enormous dividends and real estate profits through the project.

Questions are being raised on whether Lee, who had the authority to permit and approve construction works related to the project, may have given certain favors to help the company reap profits.

Prosecutors investigating allegations of preferential treatment in Daejang-dong have summoned and investigated people involved. On Monday, they also took in Kim Man-bae for questioning. Kim, who was summoned by police as a witness to the case last month, has denied all allegations.

Unless Lee clears all the doubts surrounding him, the Daejang-dong scandal is likely to hamper his presidential ambitions.

After he was nominated, the opposition party’s spokesperson Lim Seung-ho released a statement saying Lee’s defeat in the third national electoral vote proves that the public already recognizes the Daejang-dong scandal as “Lee Jae-myung gate.” He called for Lee to be investigated by the special prosecutor for the public.

“The substance and body of the case surrounding ‘Daejang-dong gate,’ such as the process of selecting a business operator, the process of designing a business to benefit the private sector, suspicion of trial transactions and suspicion of paying fees for lawyers, should be clearly identified,” Lim said.

Lee’s fate in the presidential election hinges on whether a party unity can be formed. However that is unlikely in the near future as his contender, Lee Nak-yon, strongly objects to the primary election’s outcome.

Lee Nak-yon’s camp has opposed invalidating votes won by candidates who resigned in the middle of primaries. If the votes won by candidates Chung Sye-kyun and Kim Doo-kwan, who resigned during the primary election, had not been invalidated, Lee Jae-myung’s final vote would fall short of the majority, Lee Nak-yeon’s camp claimed.

Despite their claims, Democratic Party leader Song Young-gil said Monday the party has confirmed Lee Jae-myung as its presidential candidate.

Lee Nak-yeon’s side immediately protested, releasing a statement that said Lee Jae-myung would have only secured 49.32 percent of the votes, less than a majority, had the party’s rules been correctly applied. They demanded a recount of the final vote.

“If the party rules are misread and misapplied, the legitimacy of elections may be fundamentally shaken. Even now, we need to deal with it accurately and fairly.”

The Lee Nak-yeon camp said the party could not be “one team” if a reelection is not held.