“Countless journalists have been harassed, threatened and killed. It has been my honour to belong to all those categories and now especially the last,” wrote Sri Lankan journalist Lasantha Wickramatunga in an editorial published three days after his death. A prominent editor who had criticized the authorities, he was so certain that he would face retribution that he predicted his own murder.

Across the world, nearly 90 percent of journalist murders go unpunished. Since 1992, 519journalists have been killed with impunity. And to mark World Press Freedom Day on May 3, the Committee to Protect Journalists is challenging authorities by bringing attention to the murders of 10 journalists in the past 18 years, including Wickramatunga, who were killed with impunity.

The infamous Maguindanao massacre in the Phillippines in 2009, in which 30 journalists and two support workers were killed, is “the deadliest event for the press in CPJ history” and number one on the list. Nearly 200 people have been indicted, but CPJ is doubtful that justice will be served, given the irregularities in the handling of evidence, the intimidation of witnesses and possible political influence.

The murders are many but one theme stands out: all the journalists were killed so that they would be silenced.

These are the other cases which CPJ highlights:

In 2008, Armando Rodríguez was gunned down in Juárez, Mexico, after writing an article that linked a local prosecutor’s nephew to drug cartels, and in Iraq, Soran Mama Hama was killed after linking top law enforcement officials to prostitution. In 2006, Russian journalist Anna Politkovskaya was shot because of her work on the brutalities of the Chechen separatist conflict. Hayatullah Khan was abducted and killed after exposing that the United States was operating within Pakistani borders. In 2005, Lebanese journalists Samir Qassir and Gebran Tueni died in separate, targeted bombings for criticizing Syria. Elmar Huseynov was gunned down because of his criticism against the president of Azerbaijan. In 2004, Deyda Hydara was shot after condemning the Gambian president’s threat to bury journalists “6 feet deep.” In 1998, Norbert Zongo was murdered in Burkina Faso for investigating the role of the president’s brother in a murder.

Based on its research, the organization shows that these cases can be solved if law enforcement officials simply follow the law. CPJ’s Robert Mahoney explains how the presence or absence of political will is a key element in governments resolving these cases successfully.

“What they lack is political will,” said CPJ Executive Director Joel Simon. “Solving these cases would start to change the culture of impunity around the world, a condition that produces widespread self-censorship and stifles the global dialogue.”

Also check out the “impunity index” produced by CPJ, which shows the 20 most murderous countries for journalists and graphs the beats they covered. Politics stands at a not-so-startling 44 percent, corruption accounts for 26 percent and sports (yes, sports) 2 percent.