Prosecutors charged the editor of Malaysia's leading independent current-affairs website with violating a communications law on Friday over the airing of a news video related to corruption allegations against the prime minister.
The move was swiftly condemned by Human Rights Watch as a "serious violation of freedom of the press".
Malaysiakini's editor-in-chief Steven Gan was charged in a special court for internet offences for airing the video on its site KiniTV in July. Conviction could bring a year in jail.
The video featured a news conference in which a former ruling-party member criticised Attorney General Mohamed Apandi Ali.
Apandi caused an uproar in January by abruptly clearing Prime Minister Najib Razak of wrongdoing in receiving $681mn in mysterious deposits into his personal bank account.
Gan was charged under a law prohibiting transmission of "obscene, indecent, false, menacing or offensive" content.
Premesh Chandran, Malaysiakini's chief executive, faces the same charge when he returns from a trip abroad, defence lawyer Fahri Azzat told AFP.
"My clients vigorously deny they have any intention to annoy or insult anybody," he said.
Rights groups and the opposition accuse Najib of ratcheting up pressure on critics and the media to silence the furore over the financial scandal.
The government has admitted Najib received the $681mn but claims it was a "personal gift" from the Saudi royal family that Najib returned.
However, the US Justice Department filed lawsuits in July to seize assets it said were purchased with money stolen from Malaysian investment fund 1MDB, which stated that the money transfers were not from the Saudis, but originated from 1MDB.
Authorities in several countries are investigating allegations that billions were looted from 1MDB, which Najib founded in 2009.
Najib and 1MDB deny wrongdoing.
The case showed the "increasingly dictatorial side" of Najib, Human Rights Watch's Deputy Asia Director Phil Robertson said.