Witness accounts and survivor stories from the Westgate Mall attack in Nairobi continue to emerge, telling a freighting story of violence and terror. Yet, as the investigation continues, there are still some disturbing questions about the attack that have yet to be fully explained.

Now that more access has been granted to the ruined mall, images confirm that three floors of the building collapsed, presumably because of a large explosion. The Associated Press reported today that the collapse was actually caused by the Kenyan military, supporting a claim made by the terrorists themselves. It's still not clear how or why they managed to set off the explosion, but it may have killed some (perhaps most?) of the hostages still inside the building.

The official death toll is still listed at 67, but it's likely that unrecovered bodies will be found in the rubble. As many as 60 people are still missing.

CNN is also reporting today that the terrorists did not just plant weapons inside the mall in the days before the attack, as had been previously reported, but that members of al-Shabab had rented out a store and were actually running it as functional business for nearly a year.

While investigators, including the FBI, continue their work, we're learning more about what happened inside the mall during the attack, and what those who lived through it endured. Some of the best and earliest accounts came from professional photographers who followed police into the mall after the shooting started. Nichole Sobecki and Tyler Hicks are wife and husband and both experienced war photographers. He works for The New York Times and she shoots video and photos for AFP. Both instinctively grabbed their equipment (and protective gear) and went inside, following security agents as they swept the building.

This is from Sobecki's account:

From our vantage point, I could see down to the lower floors of the mall, where the bodies of some victims of the attack lay -- their lives so unexpectedly cut short. On the first floor, a woman sprawled face down on the floor by a cafe counter waiting to be rescued, her arm held out across two young children in a gesture of protection. They were later escorted out of the mall by security forces. [...]

Amidst these scenes of horror, I was also witness to moments of fellowship. Strangers helping each other away from danger. The bravery of members of the security forces and civilians. Crowds lining up to donate blood. In a country too often characterised by its divisions, that is the small glimpse I hope I take from one of Kenya's darkest days.

Another photographer who ran toward the chaos was Goran Tomasevic, who is Reuters's chief photographer in East Africa. He tried to both document the scene and help police clear citizens out of the way. Another journalist who is used to being is dangerous situations, he was able to understand the threats he was facing and how to stay safe.

There was one moment when the police and I were hiding behind a column in the mall, sort of a stand holding something up. It wasn’t part of the building. I knocked on it and it was made out of thin material. I said “Hey guys knock on this!” Everyone started to knock. They said “So, what?” I said “It’s not going to protect us.” So, I dived down and everyone followed.

Though even the most experienced war vets can't anticipate every danger:

A policeman got shot in the stomach. He asked me to take a picture of him screaming and asked me for help. I tried to help him but I guess he was in shock or something because when I helped him up he started firing his rifle into the floor. He almost shot me accidentally. Then he dropped the weapon.

Tomasevic also captured one of the most moving images to come out of the incident, this photo of a young girl running for cover. Her name is Portia Walton, and she's the four-year-old daughter of a North Carolina couple who moved to Kenya two years ago.

Portia's mother, two younger sisters, and another woman were pinned down by the gunfire, when a man with a gun motioned for them to come toward him. The women indicated that they couldn't run with three children, so the man told them to send the oldest child by herself. The women soon followed, carrying the other two girls. (That's them in the very top photo.)

The man in the photo with the white checkered shirt was also not a policeman. His name is Abdul Haji, a Somali man living in Kenya. When he heard about the shooting, he grabbed his own gun and ran to the mall, believing the terrorist might be targeting his brother. Their father is originally from Somali, but is a former security minister in the Kenyan government, and thus no friend to al-Shabab. Haji can be seen in many other photos, helping citizens escape and even firing his weapon at the jihadis.

Here's Haji telling his story in a lengthy interview with Kenya's NTV.

Those who were in the mall when the shooting started had similar stories of confusion and fear. The attack started with explosions, then lots of gunfire that quickly it made it clear it was not just a robbery, as many originally thought. The men were dressed casually, most with scarves around their head, and were carrying AK-47 or grenade launchers.

Witnesses say the gunmen were calm, occasionally stopping to talk to certain people, and letting them go free if they could show they were devout Muslims.

About 15 minutes later, Kothari-Mashru watches as the gunman speaks quietly to one family. She can't hear what is said, but the wife is dressed in the billowing robes worn by highly observant Muslim women. Slowly, the family members stand, raise their hands above their heads, and walk away.

Other witnesses described similar scenes. Elijah Kamau, who was at the mall at the time of the midday attack, said he listened as militants told one group of their plans.

"The gunmen told Muslims to stand up and leave. They were safe," he said.

Once the news of the attack went global, people inside the mall began receiving text message from those on the outside, warning them that killers were targeting non-Mulsims, whites, and other foreigners. Those who didn't have an easy way out found places to hide; in closets, storage rooms, and even the air ducts. One woman, whose story was shared in The New Yorker, said she hid under a counter, in an exposed mall kiosk.

 

After the running and screaming died down, she heard people speaking in a language she didn’t recognize, accompanied by deliberate, slower footsteps. Through the gap between the bottom of the cupboard doors and the floor, she could see feet. She heard loud whistles, perhaps signals, and then people conferring in Swahili, the common language of Kenya. Next to African Lady is a beauty shop. “Someone, I think maybe one of the gangsters, was yelling at the people in the beauty shop to open the doors,” she said. They yelled in Swahili, “We can get in there and you can make our faces!”

Upstairs, at Safaricom, Khadija Adam heard yells from the atrium. “When I heard the words ‘Allahu Akbar!’ and the gunfire, I knew we were in trouble,” she said.

Elliot Prior, another four-year-old child found himself face-to-face with one of the gunman when his mother was shot in the leg. Elliot reportedly told the gunman he was "a bad man." The man then apologized and gave Elliot a candy bar before letting him leave unharmed, with his mother and sister.

Another American couple in Nairobi, this one from Utah, was trapped in an underground parking garage for most of the assault. The father described to Desert News how a chance encounter with a family friend on the way to mall, prevented them from being at the epicenter of the attack when it began, mostly likely saving their lives. His wife and two children hid in an maintenance shed with several Kenyans, until the husband of one of the women they were trapped with led a rescue party to them.

Unfortunately there were a number of casualties amongst people that our family knows, which has been difficult for the kids. A girl in our son's class that also rides the kids' school bus was wounded, and her father was killed. A student a year younger than our son was wounded and his mother was killed. A student that the kids know from a different school was shot and severely wounded, and his mother and a sibling were unaccounted for as of the last time we received news. The mother of a girl on our son's swim team was killed. There were quite a number of girls from our son's grade that were in the mall for a surprise birthday party. Two of them were held hostage but somehow got out. None of the others were held or injured.

Tyler Hicks, who has won Pulitzers for his coverage of Afghanistan and Pakistan, understands better than most what these conflicts are like. 

When something of this magnitude happens, it’s just as dangerous, if not more dangerous than being in Afghanistan or any other number of countries where there are wars going on. You have to think about where you’re standing, you have to think about where you have cover, the type of obstacles you can place between you and potential gunmen. A lot of the same rules apply when they’re sweeping through a building like that.

This is just plain and simple murder of unarmed civilians. It’s not a war. 

Top photo: Soldiers comb the roof of Westgage Mall, REUTERS/Noor Khamis; Second from bottom: Stephen, center, who lost his father in Saturday's attack at the Westgate Mall in Nairobi, Kenya, is comforted by relatives as he waits for the post mortem exam at the city morgue Monday, Sept. 23, 2013. (AP Photo/Jerome Delay); Bottom photo: AP Photo/Kenya Presidency