For four decades, testimony from jailhouse informants has been the source of public scandal in criminal cases across the U.S. Research shows juries find these witnesses credible, even when they know informants benefit from their cooperation with prosecutors. The impact of this practice is hard to calculate. Reporter Rhana Natour looks at critical cases in North Carolina, Pennsylvania, and California, to shed light on the issue.Find a resource guide and annotated transcript at our website here.