Four years later, none of the alleged perpetrators has been arrested alive. The motivation of the abduction also raises questions.
If, in the light of the latest declassification of documents, which occurred last May, the chronology of events is clearer, there are still many things that remain unknown as many of the documents that were released were heavily redacted.
In fact, there was little new in any of the documents, which were provided by the United Nations Mission in Mali (MINUSMA).
No known motive
As to the motive for the abduction of our colleagues there is still no explanation.
Judge Herbaut, who now heads the investigation after succeeding Judge Trévidic, has rejected pay-back as motive for the killing.
Dupont and Verlon were taken captive in the Malian city of Kidal shortly after it was recaptured from armed Islamists, then taken out into the countryside where they were shot dead.
A French TV documentary in January claimed that some of the ransom for a group of four hostages held in Niger disappeared and was never paid to the kidnappers and that the RFI reporters were murdered in reprisal.
However, a negotiator from Niger has denied that any of the ransom vanished and said there was no connection between the cases.
After the TV broadcast, the lawyers of the civil parties involved in the case had asked to question fifteen individuals mentioned in the programme.
The request was refused by the judge for reasons that are still not clear.
Finally, owing to the lack of information about the status of the main suspects still living, the French courts have yet to issue an international arrest warrant.
Were Ghislaine Dupont and Claude Verlon betrayed as the then Minister of Defence, Jean-Yves Le Drian has consistently claimed without ever explaining why that might be the case? And if so, by whom?
Another question relates to the presence of a helicopter in the sky of Kidal at the time of the murder of our colleagues, and which could have panicked the kidnappers.
It is probable that it belonged to MINUSMA according to the information relayed to lawyers working on the case, but this is by no means certain yet.
The families and friends of the two RFI reporters earlier this year called on French president- Emmanuel Macron to ensure the perpetrators are brought to justice.