Feds expand undercover operations

In recent years, a variety of federal agencies have expanded the use of undercover agents.  It's not just limited to anti-terrorism cases.  Use of such agents is nothing new and are certainly justified in many cases, but these operations always pose risks to corruption, civil rights violations, etc.  Sucn operations also often involve paid and unpaid informants who pose similar risks.  Effective supervision is one of the keys to preventing abuses.