When Burkina Faso anti-terrorism Commander Evrard Somda arrived with 20 men to start a fight-back against Islamist militants holed up in a smart hotel, his first decision was to seal off the area and throw away the rule book.
His training in France, Kenya, Senegal and elsewhere taught him he should be trying to make contact with the hostage takers. A quick glance at the horror before him was enough to know this would not work.
Cars blazed in the street, bursts of gunfire echoed from the Splendid Hotel and bodies were strewn across the terrace of Cappuccino, a cafe-restaurant across the road popular for its European menu and free WiFi.
"They wanted to kill the maximum number of people and for them it wasn't a problem to die," Somda, who arrived on the scene at 8.30 pm (2030 GMT), told Reuters in the most detailed account yet of Friday night's assault.
But Somda realized his men could not simply storm the five-storey hotel for fear of accidentally killing civilians.
"We couldn't just do what we wanted. We were obliged to take account of the life of the clients inside the hotel and avoid opening fire on them," he said.
In the event, it would be nine hours before the three attackers were cornered in the nearby Bush Taxi restaurant. They fired on a brown troop carrier at the crossroads before a machine gunner perched in the vehicle's turret shot them dead.
By then, 29 civilians from at least seven countries were dead in an attack that stamped the imprint of Islamist militancy on West Africa well beyond the previous flashpoints of Mali and northeast Nigeria.
"Many crusaders dead"
Officials have not yet been able to determine whether al Qaeda in the Islamic Maghreb (AQIM) and al Mourabitoun, groups that claimed responsibility for both attacks, used a local jihadist cell or sent fighters from northern Mali.
What is clear is that the militants selected a target to inflict maximum damage on a country emerging from a democratic transition under an elected president, Roch Marc Kabore, the first new leader since 1987.
"The intention was to hurt foreigners. It is a place where you find a lot of foreigners. That explains why they attacked it," security minister Simon Compaore said.
Another feature of the Ouagadougou attack is how much time the militants had. AQIM even said the attackers made a phone call to report to the group there were "many Crusaders dead".
A later statement monitored by the SITE Intelligence group included a photograph of three young black men in army fatigues and carrying weapons it said were used in the raid.
"I was sitting in front of my boutique. Three guys passed in front of me. The tallest had a long gun. When they got to the intersection he fired in the air and the other two went into Cappuccino," said Saly Coulibaly, who saw the attack begin at around 7.30 p.m. local time (1930 GMT).
People inside the one-room restaurant and on the terrace had no chance. Amid the shattered glass, bullet holes and charred ruins were signs of an ordinary evening brutally interrupted.
A bottle of chilli oil to serve with pizza stood on one table. A half-finished bottle of red wine lay under another.
The attackers sprayed the restaurant with bullets, set fire to cars and motorbikes and then entered the Splendid hotel opposite. From there, they fired on people in the street, including anyone trying to emerge from the restaurant.
Around midnight, a Reuters witness saw a man shot as he tried to retrieve his car parked near the hotel. He bled to death clutching his keys.
Shortly after his arrival on the scene, Somda placed armed observers in nearby buildings to determine the number of attackers, including a plain clothes officer hiding under a car.
He then withdrew to a hastily erected command post at a nearby government ministry now filling with U.S. agents, French special forces and the army and police chiefs.
By 2200 GMT, at least 60 gendarmes and police were ready to start a counter-attack alongside French special forces equipped, unlike their Burkinabe counterparts, with night vision goggles.
Two factors delayed them. First, they received mistaken information there were 12 attackers, not three.
Second, they realized that if three teams simultaneously hit the Cappuccino, the Splendid and the nearby Yibi Hotel they risked opening fire on one another by accident.
They opted first for the Splendid, the ground floor of which was on fire. Troops went room-by-room freeing dozens of people, a process that took most of the night.
At least one door was booby-trapped with a grenade and they did not know where the militants might be hiding, Somda said. Many guests refused to open their doors, fearing a trick.
In the end it turned out all the attackers had withdrawn.
Next, security forces and the fire brigade went to the Cappuccino, which had been torched.
In the Yibi Hotel they found bullet casings to show the militants had been there, but again no sign of the men. They were finally located at the Bush Taxi restaurant when the hidden security officers shot at them and they returned fire.
It then took several more hours to secure the site because of fears other militants might be hiding nearby.
In the aftermath, the grimmest scene was at the Cappuccino, where bodies were charred beyond recognition. Only one person was pulled out alive, a woman from Burkina Faso, too traumatized to speak.