But Westgate also looks like a chilling statement of intent by Ahmed Abdi Godane, the al-Shabaab leader, who consolidated his power in June in an internal coup. Among four top commanders who were executed by Godane were two of the group's co-founders, known as al-Afghani and Burhan. Al-Shabaab's spiritual leader, Sheikh Hassan Dahir Aweys, fled for his life, and was subsequently detained by Somali government forces.

The infighting continues. Earlier this month, the Alabama-born al-Shabaab commander Omar Hammami, known as Abu Mansoor al-Amriki or "the American", and a British national known as Usama al-Britani, were shot dead in a dawn raid on their hideout by Godane's allies. Hammami, who was on Washington's most wanted list, had previously accused Godane of behaving like a dictator.

Godane, also known as Mukhtar Abu Zubayr, was behind al-Shabaab's decision in 2011 to affiliate to al-Qaida and adopt its global jihadist outlook. It is Godane who is said to have ordered the 2010 bombings in Kampala that killed 74 people – in protest at Uganda's participation in Amisom. In 2011 he published a jihadist video entitled "At your service, Osama". In it he vowed that "the wars will not end until sharia [law] is implemented in all continents in the world". Even before Westgate, he was one of the world's most wanted terrorists, with a $7m bounty on his head.