But the message to the assailants who killed 30 people, mostly Westerners, in Ouagadougou was not necessarily sent from Syria.
But the message to the assailants who killed 30 people, mostly Westerners, in Ouagadougou was not necessarily sent from Syria, prosecutor Maiza Sereme told AFP ahead of the attack's first anniversary.
The communication from "one of the organisers" asked the three attackers "if everything went well, the number of people killed, and if they had a message to send to the public and those also waging jihad," Sereme said.
"The call... came from a Syrian telephone number but there is nothing to indicate the sender was indeed in Syria," she added. "The organisers... are not Burkinabe."
Al-Qaeda in the Islamic Maghreb (AQIM) claimed the January 15, 2016 attack, saying the gunmen were from the Al-Murabitoun group of Algerian extremist Mokhtar Belmokhtar.
They stormed the Splendid hotel, the Yibi hotel and the nearby Cappuccino cafe and a bar, which the men approached with guns hidden under their coats.
"They targeted Cappuccino because they knew that it was a busy time and there would be a mix of nationalities, especially Europeans," Sereme said.
At the Splendid hotel they went through guests' rooms and other areas of the hotel, shooting and wounding people. The men later destroyed their phones and SIM cards.
"We have information on their (attackers) identities and even their nationalities but we are in the process of cross-checking... to have their nationalities and real names," Sereme added.
Burkina authorities are also waiting for the FBI to pass on information from Niger, Canada and Interpol regarding the attackers' names, the weapons and mobile phone SIM cards.
Three people, a Burkinabe and two Malians, were charged in July 2016 over the attack and remain behind bars.
The strike was first such incident in Burkina Faso, and came weeks after Islamists claimed an assault on a top hotel in Bamako, capital of neighbouring Mali, in which 20 people died.
Burkina Faso prosecutors said Thursday that the investigation had "established links" between the attacks in Bamako, Ouagadougou and a deadly attack last year in the Ivory Coast town of Grand Bassam.