With overwhelming evidence such as this I think capital punishment is okay. We're not in a position where we can afford to spend money on a killer for 15 years.
It is expensive to keep a prisoner, you are right. Also, Somalia has come out of a state of lawlesness for 2 decades, maybe harsh sentences are needed right now. I don't know to be honest. Like I said the judicial system in Somalia needs a thorough review. However, which system in Somalia doesn't need a thorough review; every sector: agriculture, urban planning, transport, health care, education needs a review.
The task of the Farmaajo/Kehyre government huge, and they can't do it alone . All Somalis need to do their bit I suppose.