Sardasht Osman, 22, was kidnapped on May 4, 2010 in the Iraqi Kurdish regional capital Arbil, not long after he wrote articles critical of the government and ruling parties. His corpse was found a day later in the restive northern city of Mosul with a single bullet to the head.

However, an official inquiry formed by regional leader Massud Barzani said last year that the university student was killed because of his ties to a militant group, which subsequently denied it had shot him.

"We question the Kurdistan regional government's determination to shed light on this murder and condemn the lack of transparency surrounding its investigation," Paris-based watchdog Reporters Without Borders (RSF) said.

Aref Qarbani, the editor-in-chief of independent Kurdish newspaper Arso, called to "reopen the inquiry, and form a neutral committee to investigate the case."

"The last committee was not neutral," Qarbani said.

Osman's own family reiterated its rejection of the inquiry's findings, with the dead writer's elder brother Bakr insisting Sardasht "was killed because of his critical articles about the lack of social justice in the region."

A spokesman for Barzani was not immediately reachable by AFP for comment.

In one of Osman's most critical articles, headlined "I love the daughter of Massud Barzani" and published in the Kurdistan Post, he used an imaginary dream to condemn the alleged corruption of Kurdish leaders.

"When I become the son-in-law of Barzani, the wedding night will be in Paris and we will visit the palace of our uncle for several days in the United States," he wrote, drawing a provocative contrast between Barzani's opulent lifestyle and that of ordinary Kurds.