In the 1980s, a new type of “skilled witness” began emerging: the law enforcement officer. In criminal cases, the Government began calling law enforcement officers to testify as experts on what we referred to as “the nature and structure of organized crime families.” United States v. Daly, 842 F.2d 1380, 1388 (2d Cir.1988). This Court first reviewed a challenge to the use of such an expert in United States v. Ardito, 782 F.2d 358 (2d Cir.1986). The Government had called an FBI agent to testify as an expert about terms such as “captain,” “capo,” “regime,” and “crew.” Id. at 363. We upheld the admission of that expert testimony because it “aided the jury in its understanding of” recorded conversations between the two defendants. Id. Furthermore, we noted, the district court had reminded the jury that the defendants there had not been charged with any conduct relating to organized crime. Id.
One year later, we upheld the admission of expert testimony by a law enforcement officer on the related matter of the meaning of messages written in code. United States v. Levasseur, 816 F.2d 37, 45 (2d Cir.1987). Upholding such testimony was consistent with pre- Ardito cases where we and other Circuits had allowed law enforcement officers to testify as experts about the meaning of jargon relating to narcotics trafficking. E.g., United States v. Borrone-Iglar, 468 F.2d 419, 421 (2d Cir.1972) (upholding a law enforcement officer's testimony “concerning the narcotics vernacular used in [recorded] telephone conversations”); see also United States v. Theodoropoulos, 866 F.2d 587, 590-91 (3d Cir.1989) (describing testimony “concerning the meaning of ... coded conversations” as “the paradigm situation for expert testimony under Rule 702”) (overruled on other grounds).
In subsequent years, we have encountered novel uses of these “officer experts” and approved of their testifying on a broader range of issues. For example, in United States v. Daly, 842 F.2d 1380 (2d Cir.1988), where the defendants were charged with “various crimes arising out of activities of the Gambino crime family,” we upheld the expert testimony of an FBI agent who “identified the five organized crime families that operate in the New York area” and “described their requirements for membership, their rules of conduct and code of silence, and the meaning of certain jargon.” Id. at 1383, 1388. After the Government had played surveillance tapes for the jury, the agent interpreted the jargon the speakers had used. Id. at 1384. This Court upheld the district court's decision to admit the agent's testimony, finding that the agent had testified about “much that was outside the expectable realm of knowledge of the average juror.” Id. at 1388. The district court's judgment that the agent's testimony would be helpful to the juror “was not unreasonable.” Id. Finally, the agent had not testified about the defendants or any of the charged offenses. Id. The only offense element to which the agent had testified “was the existence of a RICO enterprise, as he gave his understanding of the existence of organized crime and the Gambino family.” Id.
Since Daly, we have repeatedly upheld the admission of similar testimony. See, e.g., United States v. Locascio, 6 F.3d 924, 936 (2d Cir.1993) (upholding an FBI agent's expert testimony about the internal operating rules of organized crime families, the meaning of recorded conversations, and the identification of members of the Gambino crime family); United States v. Feliciano, 223 F.3d 102, 109 (2d Cir.2000) (upholding an FBI agent's expert testimony about “the structure, leadership, practices, terminology, and operations of [a street gang, Los Solidos]”); United States v. Matera, 489 F.3d 115, 121 (2d Cir.2007) (upholding the admission of an officer's expert testimony “about the composition and structure of New York organized crime families” and observing that the district court had limited the expert's testimony to general information rather than information about the defendants themselves). Our decision to permit such expert testimony reflects our understanding that, just as an anthropologist might be equipped by education and fieldwork to testify to the cultural mores of a particular social group, see Dang Vang v. Toyed, 944 F.2d 476, 481-82 (9th Cir.1991) (upholding the district court's admission of expert testimony on Hmong culture), law enforcement officers may be equipped by experience and training to speak to the operation, symbols, jargon, and internal structure of criminal organizations. Officers interact with members of the organization, study its operations, and exchange information with other officers. As a result, they are able to break through the group's antipathy toward outsiders and gain valuable knowledge about its parochial practices and insular lexicon. Allowing law enforcement officers to act as experts in cases involving these oft-impenetrable criminal organizations thus responds to the same concerns that animated the enactment of the criminal laws that such organizations (and their members) are typically charged with violating, such as the Racketeer Influenced and Corrupt Organizations Act, 18 U.S.C. §§ 1961-68, and the more recent Violent Crimes in Aid of Racketeering Act, id. § 1959. See Organized Crime Control Act of 1970, Pub.L. 91-452 pmbl., 84 Stat. 922, 923 (1970) (“[O]rganized crime continues to grow because of defects in the evidence-gathering process of the law inhibiting the development of the legally admissible evidence necessary to bring criminal ... sanctions ... to bear on the unlawful activities of those engaged in organized crime....”).