The IRS Criminal Investigation Handbook describes in 95 chapters the procedures for investigation of crime, preparing for trial and a host of other activities including undercover operations and surveillance: http://cryptome.org/irs-ci/irs-ci.htm The handbook aptly describes the variety of methodologies used in the Bell and Parker cases, in particular covert methods used to induce criminal actions for entrapment, as well as massaging trial testimony of witnesses and agents. The chapter on Undercover Operations provides for covertly attending client-attorney sessions; posing as an attorney, physician, clergyman, or member of the news media; obtaining through false pretense privileged information from attorneys, physicians, clergy and news media; giving false testimony; putting innocent parties at risk of physical violence; carrying out criminal actions; and earn income to offset cost of the operations ("churning"): http://cryptome.org/irs-ci/36211a.html The chapter on Surveillance and Non-consensual Monitoring states: "It is important to distinguish between investigative techniques used in surveillance activities and certain undercover operations. The following characteristics apply to surveillance: The purpose is to observe ongoing activities and individuals. Interaction with subjects and third parties is usually not initiated. Conversations are incidental to the surveillance. Conversations are not monitored or recorded, except as set forth in above. The special agent has limited cover, used to protect the integrity of the surveillance. Local special agents are used. Special agents need not be trained in undercover techniques. Initiated surveillance activity bears little resemblance to an undercover operation. The following situations indicate the surveillance activity evolved into an undercover operation: The activity continues for an extended period, and begins to focus on certain individuals. Reliance on cover identities increase. Contacts with targets and other individuals are more in-depth. Agents become participants rather than observers of the activities of interest. The following characteristics apply to undercover operations: The purpose is to initiate or participate in activities with identified targets. Interaction with subjects and third parties is sought. Undercover agents or other authorized individuals initiate and direct conversations to further the objectives of the operation. Conversations may be monitored and recorded. The undercover agent has a documented cover. This cover is used as a basis for contacts with targets or witnesses." http://cryptome.org/irs-ci/36209a.html