I can tell you—and this is basically premised on police experience and dealing with people at the time we're interviewing them—there is a correlation between their knowing that the perpetrator or person against whom they are talking is in the judicial system, in jail, or out of reach and basically out of harm's way, and a better intention on their part to work or cooperate with law enforcement, from a general perspective.
On June 11th, 2009. See this statement in context.