Two days after the siege at Nairobi's Westgate mall ended, authorities from around the world are still searching for victims and evidence. Officials have confirmed that at least 67 people died in the attack, and the Kenyan Red Cross estimates 61 people remain missing, though Kenya's Interior Minister told the BBC he expects to find an "insignificant number of bodies."

Forensic experts from the US, the UK, Canada, Germany, and Interpol have joined the investigation, which is expected to take at least seven days.

For American investigators, the search is doubling as intelligence gathering about al Shabab's future plans.

“We are in this fight together,” Robert F. Godec, the American ambassador to Kenya, told the New York Times. “The more we know about the planning that went into this, the way it was conducted, what was used, the people involved, the better we can protect America, too.”

More than 20 F.B.I. agents are already investigating the attack, and dozens more – some of them members of the New York Joint Terrorism Task Force – are on their way.

From the New York Times:

Over the next few days, agents, including a full Evidence Response Team, will be collecting D.N.A., fingerprints and other biometric information, poring through surveillance footage and examining guns, laptops, cameras and computers — anything to gain insights into how the attack was carried out and the hierarchy, planning and structures behind the group, especially if they have any ties back to the United States.

Adding to US concerns is the fact that over two dozen Americans have reportedly been recruited or joined al Shabab forces in Somalia. And there's the precedent of terrorist attacks in Kenya being followed up by attacks in the United States – the 9/11 attacks came just three years after a then-relatively unknown al Qaeda bombed US embassies in Kenya and Tanzania.

A picture of the mall's parking lot, from CBS News:

[Top image via AP]