The chief editor of the now-defunct website The Online Citizen (TOC) was jailed for three weeks for criminal defamation.
Terry Xu Yuanchen, 39, was found guilty in November last year of defaming members of the Cabinet of Singapore by approving the publication of a letter on Sept 4, 2018, that alleged "corruption at the highest echelons".
The writer of the letter, Daniel De Costa Augustin, 38, was sentenced to three months and three weeks jail. He will start serving his sentence on May 4.
De Costa was convicted of a similar charge of criminal defamation and a second charge of unauthorised access to an email account not belonging to him, which he used to submit the article.