Often writing at his kitchen table, Rafael Marques de Morais, a journalist and human rights advocate, needles Angola's ruling establishment with reports on alleged wrongdoing by officials, military figures and business executives. A rare voice of criticism in this southern African country, he is often in trouble.

Last month, for instance, Marques was found guilty of libel and defamation after publishing a 2011 book that alleged that a group of generals and three companies were linked to human rights abuses at diamond mines. The book details more than 100 killings and 500 instances of torture that Marques alleges were carried out by private security firms owned by the generals, with members of the Angolan army allegedly participating in some of the abuses. The generals denied the accusations.

Marques, who runs Maka Angola, an investigative news website, asked the attorney general to look into his book's findings. Instead, he was sucked into a legal battle that at times bewildered him. He was charged, then the charges were dropped, then they were reinstated and he went to trial, at the end of which he was given a six-month suspended sentence, meaning he can be jailed for six months if his reports are believed to be defamatory or libelous during the next two years.

"They put this cloud hanging over my head so, anything they don't like for two years, they can lock me up for that," Marques said. In April, his site was hacked and he is unable, at least for now, to post updates.

Marques has received awards abroad and international rights groups criticized his trial, accusing the Angolan government of manipulating the court. The U.S. State Department said it was concerned by the negative impact Marques' conviction will have on freedom of expression in Angola. His investigations are not widely known inside Angola, though, because of its restrictive media environment, said Lara Longle, editor and writer for news outlet Rede Angola.

Angola's minister of justice and human rights, Rui Mangueira, said Angolan citizens and the press can express themselves freely as long as they do so "appropriately" and do not undermine the Constitution, state-run news agency Angop quoted him as saying in May.

Marques, 43, has long been an agitator.

In 1992, as a rookie newspaper reporter, Marques pushed for better working conditions. More than 40 journalists shared 10 typewriters and one telephone that was held together with a rubber band, he said. Their reports were increasingly censored by the newspaper's editors.

Marques said in a Skype interview with The Associated Press that he was once detained for calling President Jose Eduardo dos Santos, in power since 1979, a dictator in a newspaper article. That time, Marques was detained for 43 days and sentenced to six months in jail, suspended for two years, which he learned about via state radio.

After Angola's civil war ended in 2002, the country became one of sub-Saharan Africa's top two oil producers. Rapid development followed, creating more opportunities for corruption.

Angered by what he saw happening to his country and branded a troublemaker in local media circles, Marques founded Maka Angola in 2009. In Kimbundu, Marques' first language, maka means a problem that must be solved. On his site, Marques reports on how millions of dollars could have disappeared from Angola's state oil company, corrupt dealings in the diamond sector and alleged incompetence of state officials.

Marques co-authored, for Forbes, a story on how Isabel dos Santos, the president's daughter, became a billionaire. He said that state media, in apparent retaliation, reported that Marques was a CIA spy and a traitor.

For Marques, investigative reporting remains a passion, and he must also keep pushing not only for the means to publish his findings but also for the right to do so.

"Here I cannot only write," he said. "I have to defend the space for me to be able to write because that space is under constant harassment, under constant threat."