As I was saying and vfr440 was confirming,
According to eye-witnesses, the gunmen told Muslims to leave the centre shortly before midday and said that non-Muslims would be targeted.
The attackers had asked, “who is Prophet’s mother?” in an attempt to discover non-Muslims. One man escaped by showing the attackers his ID with his name, Hakim, on it. Another reportedly failed to name the Prophet’s mother and was killed.
Horror in Kenya: 'al-Shabaab claim responsibility as non-Muslims targeted in terror attack' on Nairobi shopping centre - Africa - World - The Independent
Being "white" in East Africa is not how it was 10, 20 or even 30 years ago. Things have changed and white expats working in the region need to be aware.