Here is an interesting article from Akron Ohio about a sexual relationship between a female officer and her informant. What is interesting about this case is that by the account given the agency seem to have had in place policy that would have mitigated the risk of this occurring. ALL contacts had to be reported and two handlers always present.
Careless or negligence - managing confidential informants
Reducing Confidential informant Related Corruption
This article relates to informant management that resulted in a Chicago police officer being sentence to seven years imprisonment. This story is not about one bad cop, it is about a broken system for managing confidential informants (Confidential Human Sources, HUMINT, Covert Human Intelligence Sources , CHIS)
Confidential Informants Review of Houston Police Narcotics Unit
Active listening for police - a skill for conflict avoidance.
Confidential Informant Management - The Need for Dedicated Source Units
An extract from our forthcoming publication HUMAN SOURCES: MANAGING CONFIDENTIAL INFORMANTS. It will be out in July and details the structures need to manage human sources safely and more effectively In the meantime here is a section on the need to mage sources using dedicated officers in Dedicated Source Units.