"The investigation is advancing," said prosecutor Boubacar Sidiki Samake, who is in charge of the anti-terrorist probe.
Samake said police hoped to soon "flush out the attackers and bring them to justice," adding that "it is clear that they had accomplices who helped them come to the hotel."
"You will see developments in the coming days," he said, adding that police had staged several raids on homes.
The attack has been claimed by two separate jihadist groups and a manhunt launched for three suspects.
Also Read
Gunmen went on the rampage at the Radisson Blu hotel from early morning on Friday, shooting in the corridors and taking 170 guests and staff hostage.
The assault, which ended when Malian and international troops stormed the building, left 19 people dead, including 14 foreigners, as well as two attackers, according to a "definitive" report by the government.
The UN peacekeeping force in Mali, MINUSMA, however spoke of 22 fatalities, including two attackers.
Senegal's President Macky Sall visited Bamako yesterday to show national solidarity and the support of the West African regional bloc ECOWAS which he chairs.
"Mali will never be alone in this fight, we are all committed because we are all involved," he said, announcing that Mali's neighbours Senegal, Mauritania and Guinea would also observe three days of mourning.
The Al-Murabitoun group, an Al-Qaeda affiliate led by notorious one-eyed Algerian militant Mokhtar Belmokhtar, has claimed responsibility for the attack.
In a recording broadcast by Al-Jazeera, a spokesman identified them as Abdelhakim al-Ansari and Moez al-Ansari, the term "al-Ansari" indicating they were indigenous jihadists.
But a jihadist group from central Mali, the Macina Liberation Front (LWF), also claimed the attack in a statement sent to AFP yesterday, saying it was carried out by a squad of five, including "three who came out safe and sound".