"Who are the killers, who gave the orders, what are the circumstances and why?" Pierre-Yves Schneider, spoke person for the Friends of Ghislaine Dupont and Claude Verlon asked at a press conference on Thursday.
The pair were shot dead on 2 November 2013 after being kidnapped in Kidal, northern Mali.
And, although Al Qaida in the Islamic Maghreb (Aqim) claimed responsibility for the murders, inquiries by Malian and French investigators have failed to find out exactly what happened.
"In general there is little information on how the Malian judiciary is handling this case," Schneider said. "But we learned very recently that the judge who has been put in charge of the case is not part of the anti-terrorism section that was created in Bamako in 2013.
"So that’s what is so surprising, it's weird."
About 100 official documents were recently declassified by French Defence Minister Jean-Yves Le Drian but large parts of them have been redacted, according to Schneider.
The documents are believed to have been classified because of Kidal's strategic situation, on the edge of a region that is a source of uranium for both civilian and military purposes.
What does Hollande know?
And the group wants to know what Hollande meant when he told journalists Gérard Davet and Fabrice Lhomme that French hostage Serge Lazarevic, who was freed in 2014, was "doubtless held by the people who killed the two journalists and seem to have killed [another French hostage Philippe] Verdon".
The statement is published in the book Un Président devrait pas dire ça (A President shouldn't say that), based on a series of interviews Hollande has given to the reporters throughout his term of office.
"We'd like to know more about that little phrase," Schneider commented.
The group is looking into the theory that Dupont's and Verlon's murderers were involved in negotiations to free Lazarevic.
"The circumstances of the tragedy still raise many questions," 20 journalists' associations from RFI and other media said in a statement Thursday. "And we have the unpleasant feeling that everything possible has not been done to bring the truth to light in this affair."
Cartoons in solidarity
Paris's La Maison des Journalistes, which trains young reporters, is hosting an exhibition of cartoons about the case.
"The residents we have at the moment are Afghans, Rwandans, Syrians, Uzbeks and Turks," director Darline Cothière told RFI. "I've seen them looking at the drawings for a long time, no doubt because the persecutions referred to by the cartoonists echo their own experiences.
"Ghislaine Dupont and Claude Verlon have become their heroes in a way."