In the story, it was said that Ganapathy has links with the Malaysian government as well, and that he had written a biography, titled Taib - the Visionary, of Sarawak state's Chief Minister Abdul Taib Mahmud, according to SCMP.
"I trust my reporters and my editors and I think that being journalists, we made the right decision. I acted according to journalistic professionalism, but the company said they can not keep me in my position".
Outgoing publisher Bill Clough announced the sale in a press release on Saturday, welcoming Sivakumar - also known as Siva - to the role and praising his credentials.
The incident followed requests from new management to take down a story about the links of its new owner to Cambodia's ruling elite.
Phil Robertson, the deputy Asia director of Human Rights Watch, described the deal as "a staggering blow to press freedom in Cambodia".
The Post has also been dogged by an ongoing legal action launched by former chief executive Chris Dawe for wrongful dismissal during his tenure at the paper.
All stories must now be approved by Purushotman in what critics of the sale, and subsequent events, have said is a further worrying sign that the Post's independent voice has been silenced.
Managing editor Stuart White, who has worked for the Post for six years, was the first staff member to refuse to remove the article. Chief ececutive Marcus Holmes was the last to tender his resignation. The Cambodia Daily filed for bankruptcy and shut down last September after being ordered to pay $6.3 million in back taxes. Management refused, and Kimsong was sacked shortly after.
In a statement reportedly from Mr Sivakumar circulating on social media, he described the Post's report as a "disgrace" that "borders on internal sabotage" and said he now had "serious doubts" about the calibre of journalists at the paper.
The Phnom Penh Post reported that it had received a statement from its new owner saying he was "fully committed" to upholding the paper's editorial principles and independence.
Hun Sen has been consolidating his power ahead of a Lower House election in July.
Asia PR lists Cambodian dictator Hun Sen as former client.
The Post was founded in 1992 as Cambodia sought to re-establish stability and democracy after the tumult of genocidal Khmer Rouge rule in the late 1970s and subsequent fighting between its guerrillas and the communist government that succeeded it. "I wish the fantastic journalists at The Post all the best", tweeted Brendan O'Byrne, the business editor.
Last year, the leader of the largest opposition party was arrested on charges of treason and the party was later forced to dissolve.
Cambodia ranked 142 out of 180 worldwide locations on the 2018 World Press Freedom index compiled by Reporters With out Borders.
The Post's sale may indicate that Hun Sun's administration has decided that it no longer needs to allow a free media to operate in the country as a concession for getting Western aid, said Shawn Crispin, the Bangkok-based Southeast Asia representative for the Committee to Protect Journalists, a nonpartisan advocacy group based in NY.