Kenya is marking the one year anniversary of the Westgate shopping mall siege, when gunmen stormed a upscale mall in Nairobi and battled with security forces. The Islamist Somali group, Al Shabaab, claimed responsibility for the attack that left 67 people dead. One year on, Kenya's security forces have been accused of failing to act on intelligence reports that an attack was imminent. Al Jazeera's Catherine Soi reports from Nairobi.