The Post's sale may indicate that Mr. 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.
Editor Kay Kimsong said he was sacked for signing off on a piece exploring the implications of the sale.
Kay Kimsong, who had worked at the Post for 10 years, told The Associated Press that the representative of the newspaper's new owner had told him he made a big mistake by allowing the publication on the front page of the article saying a PR firm linked to the prime minister had bought the Post.
In a statement on Saturday, Mr Clough said the tax issue had been resolved, and that the sale was prompted by a "worldwide decline in market share for newspaper advertising" which had also been felt in Cambodia. Its website says, without elaborating, that Mr. Hun Sen's "entry into the government seat" was among its government-related projects.
"I resigned this morning after being told to take down the The Post's story on its sale, which I refused to do", Stuart White, the former managing editor of the English-language paper told AFP.
But journalists and media watchdogs across the region have raised doubts about the paper's future independence due to a number of concerning links between the Post's new owner and the Cambodian and Malaysian governments.
The Phnom Penh Post had been the subject of a $3.9m tax bill, which drew widespread parallels with the circumstances surrounding the shuttering of former English-language publication the Cambodia Daily. Clough stated that the Post's tax bill had been settled as part of the sale.
The story was still available on Monday afternoon on the The Post's website. "I didn't feel like I could do that in good conscience, so I resigned immediately".
Written by business editor Brendan O'Byrne and national reporter Ananth Baliga, who have both resigned, the article detailed Sivakumar's links to high ranking Cambodian and Malaysian officials. CEO Marcus Holmes was the last to tender his resignation.
Kimsong, O'Byrne and Baliga were all targeted by Sivakumar in an internal memo savaging the Post's coverage of the newspaper's sale, with the new owner calling on all three staff members to be "terminated".
Sivakumar said in a press release distributed to staff on Saturday that he meant to maintain the newspaper's editorial independence.
He has said he will uphold the Post's legacy and editorial independence.
The Post reported that his PR company had done business in the past for the government of Prime Minister Hun Sen, which has curtailed press freedom ahead of a July general election.
Daniel Bastard, head of the Asia-Pacific desk of Reporters Without Borders, expressed his solidarity with the Post's journalists.
The crackdown also saw dozens of radio stations taken off air and the jailing of two reporters from Radio Free Asia.
I have every confidence that the reporters and editors there will keep carrying the torch for press freedom in Cambodia.