The Role of Undercover Agents in Criminal Investigations

The FBI uses undercover agents to investigate a wide range of high priority cases, including public corruption, terrorism, narcotics, and organized crime. Agents infiltrate criminal organizations to gather evidence and build relationships that can lead to arrests.


Undercover officers are subject to certain risks, such as entrapment, which is prohibited by the Guidelines. To prevent this, a SAC must submit an application to FBI Headquarters for any Group II undercover operation in sensitive circumstances.


Many famous undercover agents have played a major role in helping to bring down organized crime. In the 1970s, FBI agent Joseph Pistone infiltrated the Mafia families of Bonanno and Colombo in New York City, exposing members and their associates. He was close enough to see two family members murdered, have a $500,000 contract put on his head and be targeted for his own murder. His work resulted in more than 100 convictions.

Sting operations are often used in investigations involving proceeds of crime and money laundering. FBI agents posing as businessmen have established elaborate storefront money laundering operations in retail stores to intercept wire transfers and other financial transactions (see sting operation).

In the Prohibition era, an FBI undercover agent posed as a gangster to smash a West Coast version of “Rum Row.” He arranged for a shipment of illegal Canadian booze from a ship docked in San Francisco to go into a warehouse where he would wait. When the money changed hands, the gangster fired off a flare, alerting the US Coast Guard to board the ship and arrest the bootleggers.

In a white collar crime investigation, FBI undercover agents posing as licensed attorneys assumed roles as county prosecutors and private practitioners to uncover kickbacks between judges and attorneys in a Chicago courtroom. They exposed judges who took bribes to dismiss cases and attorneys who received kickbacks for assigning cases to them. More than 100 manufactured crimes were uncovered in the Greylord operation, resulting in numerous convictions and jail time for many judges, attorneys and other public officials.


Undercover agents can make significant contributions to criminal investigations. They have been instrumental in breaking up organized crime syndicates; infiltrating public institutions such as schools, police departments, and political organizations; exposing fraud and embezzlement within private corporations; and targeting a wide range of white collar crimes.

However, the undercover approach has its drawbacks. For example, it exposes agents to considerable danger and can negatively impact third parties through entrapment (i.e., encouraging suspects to commit crimes they would not otherwise commit) and agent provocateur activities. Jurisdictions vary in their restrictions on such operations, but many prohibit encouraging suspects to commit crimes through entrapment or through the use of an agent as a provocateur.

In addition, undercover assignments are typically assigned to less experienced investigators who can be susceptible to problems in the field. For example, interviews with undercover officers indicate that they sometimes feel that their supervision in the field is insufficient. This may be related to a tendency for undercover investigators to be younger and less experienced than other FBI officers, a factor that has been associated with poor performance and morale.

Finally, undercover operations can be complicated and time consuming. For example, a drug investigation that requires an undercover officer to infiltrate a drug dealer’s operation can require weeks or months of surveillance. Another example is a sting operation to identify corrupt judges and attorneys. Such an operation can take years to complete and involve dozens of undercover officers, many of whom must maintain their cover for long periods of time.


Infiltrating gangs and organized crime groups carries significant risks for undercover agents, who may be exposed to violence or death. Moreover, the work can be stressful and taxing on the body, requiring a strong character and an ability to perform under pressure.

In addition, officers can find it difficult to reintegrate into police life after an undercover investigation. They can find it difficult to adjust to a normal lifestyle and may become cynical, suspicious or paranoid. They often lose sleep and suffer from a lack of physical activity. As a result, some develop health problems such as high blood pressure and depression.

Depending on the case, undercover agents may also be required to testify in court, which can be a highly stressful experience. They must reveal a minimal amount of information in order to maintain their cover and protect confidential operational details, yet they must be able to communicate effectively and withstand cross-examination.

Lastly, undercover operations can expose the agency to liability if agents’ identities are revealed by criminal suspects. This risk is exacerbated by the extended time that undercover investigators spend infiltrating their targets. For example, a Canadian undercover operation targeted currency-exchange houses where criminals exchanged large sums of cash, exceeding the $10,000 threshold currently requiring reporting to Canada’s financial intelligence unit. The undercover agent posed as a teller and helped to uncover illegal activities, resulting in charges against 36 corporations and 65 individuals.


The psychological and personal impacts of undercover work can be significant. Agents must adopt behaviors and false personal characteristics that are often contradictory to their own beliefs and personalities, and they may have to spend extended periods of time in isolation from their family and coworkers. The stress of undercover assignments can also lead to mental health issues, including depression and substance abuse, and difficulties in reintegrating into normal duty after the assignment is over.

The FBI relies heavily on undercover techniques for investigating a wide range of criminal activities, from drug trafficking to public corruption. For example, a recent undercover operation infiltrated a motorcycle gang in New England and led to 17 convictions and the recovery of stolen guns, vehicles, and motorcycles. In addition, a number of criminal enterprises have been brought down by undercover investigations, such as the opium and cocaine distribution organization targeted by the FBI in South Dakota.

To ensure that the FBI is operating undercover operations in accordance with its guidelines, USOU has a specialized unit within its Operational Support Section, which works with field offices and HQ’s operational units on proposals for Group I undercover operations that are to be submitted to the CUORC for approval. The USOU unit prepares a detailed document describing the proposed undercover operation, anticipates questions that the CUORC will have, and provides instructions for conducting and closing down the operation. It also reviews CUORC meeting minutes and other documents to determine whether the CUORC has complied with the undercover guidelines.