A senior Malian military intelligence officer who was investigating al-Qaeda in North Africa has been shot dead in the northern city of Timbuktu.
Lt Col Lamana Ould Cheikh was gunned down at point blank range by two men in his own home.
Earlier this week Mali's president said the army had detained three members of the militant group, which last week said it had killed a British hostage.
The assassinated officer is thought to have been behind two of those arrests.
If al-Qaeda in North Africa carried out the shooting, as officials suspect, it would be the first time the group has successfully directly targeted an officer of the Malian security forces, say correspondents.
A member of the dead man's family, Lamana Ould Bou, told AFP news agency that two of the gunmen came into their house while two others stayed outside in a getaway vehicle.
"They came into our house. The lieutenant colonel was sitting in the living room and one of the men pointed at him and said to the other: 'That's him, that's him.' Then they shot him three times," he said.
Briton Edwin Dyer was in a group of European tourists attending a festival on nomad culture when he was kidnapped in Niger in January, then taken into Mali by his captors.
The militants carried out their threat to kill him because the British government did not free a radical Muslim cleric, Abu Qatada, from a UK prison.
A Swiss citizen, Werner Greiner, captured alongside Mr Dyer, is still being held.