Speaking to the press in Dakar after being briefed on the state of the investigation, the group said they believed “major suspects” had been identified.

Journalists Ghislaine Dupont, 57, and Claude Verlon, 55, working for France's state-owned world news service RFI, were abducted and killed in Kidal, in northern Mali, on November 2nd, 2013.

The murders have long been suspected to have been revenge for a French military campaign, Operation Serval, that chased out jihadists from the region a few months earlier.

But a rival theory, aired this year in a programme on France 2 television, is that they became ensnared in a hostage drama that was unfolding in Niger – their deaths suspected to have been ordered by hostage-takers angry that they had not received their share of the ransom for freeing captives.

“Major suspects are believed to have been identified,” said Pierre-Yves Schneider, spokesman of the group Friends of Ghislaine Dupont and Claude Verlon.

“Two were 'neutralised' in military operations and one reportedly died in a motorbike accident,” he said.

“But two or three others are believed to still be alive, and free, apparently on the Algerian side of the border.

“Everything must be done to have the suspects arrested, even if they are in Algeria. If they are killed or remain free, there will have been no justice.”