This points to the need for trust building to go beyond inter-personal trust and for leaders to understand the formal and informal organizational governance structures that build and buttress trust within and between organizations.

FORBES: Why Trust is the New Core of Leadership

Nuzzi's book highlights an internal power struggle within the Vatican through numerous documents including faxes, personal letters and inter-Vatican memos.

CNN: No cardinal suspected of pope papers leak, Vatican insists

That the great majority of gang homicides involve a firearm and took place in public suggests that inter-gang conflict and retaliation (perhaps territory disputes, personal beefs or just defending reputations) as the main causes of killings.

ECONOMIST: Gang violence