Around a dozen assailants were involved in the attack on a Nairobi shopping mall that has left at least 68 dead, The Standard newspaper reported on Monday after examining security camera footage.
The footage confirmed witness accounts that the attackers -- armed with grenades, rifles and pistols and loaded with ammunition -- stormed the mall from both the front and rear.
The biggest group came in through the front entrance and attacked a caf? with gunfire and a grenade.
Another group of four attackers wearing headscarves came in through the entrance to the multi-storey car park after shooting a guard.
That group then continued up to the rooftop carpark where a party was being hosted by a local radio station.
The attackers hurled two grenades into the crowd, but only one exploded.
The attackers threw a grenade at the door leading from the upper carpark into the mall, causing the door to block. They then forced it open with rifle fire, before shooting shoppers and staff inside.
People were ordered to recite the Islamic creed, according to several witness accounts. Those able to recite at least the first couple of words were spared. Those who were unable were shot.
"When I mentioned the first word of the Shahada (creed), they moved on. That is how I survived," one survivor was quoted as saying by The Standard.
Meanwhile the larger group was fighting at the front of the mall.
"The gang was armed with rifles which gave them an advantage over those who tried to engage them," said a witness who was armed at the scene.
The group fought its way upstairs as their accomplices who entered from the top carpark made their way down.
The footage then showed gunmen subjecting toilet doors to a barrage of gunfire, apparently after learning that large numbers of people were holed up inside.
It then showed some of the attackers retreating into cinemas on the top floor while others headed into a control room of a supermarket.