Opposition protests are both rare and short in Angola because they are always quickly shut down by police. That’s why a small group of activists chose to assemble at night to protest a court decision to sentence watchdog journalist Rafael Marques de Morais to a six-month suspended sentence.

The prize-winning journalist is known for his investigations into the “blood diamond” trade in Angola. He worked with the Observers to release a video showing the torture of mine workers last year. Last week, Marques de Morais was found guilty of defaming several high-ranking generals in his 2011 book on blood diamonds in which he linked the men to murder, torture and land grabs.

The prosecutor in the case said that Marques de Morais had confessed and even apologised. Marques de Morais denies these claims and says he wants to appeal the ruling.

Campaign groups, including Index on Censorship, called the trial an "absurd process" and said they were "appalled" by the ruling.

At 10:10pm local time on Sunday, activists assembled quietly in front of the journalist's home to show their support. They filmed the event, but kept their assembly brief so that they wouldn’t be caught by authorities.

Several well-respected NGOs, including both Amnesty International and Human Rights Watch, signed a letter to Angolan President José Eduardo Dos Santos asking him to drop the charges against Marques de Morais.

Marques de Morais is a regular contributor to the Observers site. Last month he appeared on both our website and our show to talk about the massacre of members of a religious cult by Angolan authorities.