Robow defected to the government over the weekend. He was one of the founders of al-Shabab, along with other radical leaders following the defeat of the Islamic Courts Union in late 2006.
He quickly rose in the group's ranks to become its official spokesman and a deputy leader. He, however, fell out with the al-Qaeda-linked group’s leadership in 2013, and remained a fugitive in the remote areas of south-western Somalia until his surrender.
In June, the US State Department withdrew Mr Robow from its terror list and lifted the $5m (£3.8m) reward for information leading to his capture. He announced his defection to the Somali government in August.