All persons seeking admission to the United States must demonstrate to a U.S. Department of Homeland Security (DHS) Customs and Border Protection (CBP) inspector that they are a foreign national with a valid visa or passport or that they are a U.S. citizen. The United States does not require its citizens to have legal documents that verify their citizenship and identity (i.e., national identification cards). The Immigration and Nationality Act (INA) furthermore requires employers—when hiring citizens and foreign nationals alike—to verify employment eligibility and establish identity through specified documents presented by the employee. Immigration fraud is reportedly widespread, though reliable estimates of its pervasiveness are not available. Many experts say that document fraud increased following the enactment of the Immigration Reform and Control Act of 1986, which first required employers to inspect the documents of prospective employees. Large-scale black market enterprises of counterfeit immigration documents and "breeder" documents grew up to supply unauthorized alien workers with necessary papers. Given that an estimated 12 million foreign nationals are residing in the United States without legal authorization, it is reasonable to presume that many of these unauthorized aliens are committing document fraud. The extent to which unauthorized aliens enter with fraudulently obtained documents or acquire bogus documents after entry is not known. Among aliens coming temporarily to the United States, however, committing fraud to obtain a nonimmigrant visa has been an ongoing problem. It is also possible that many of the people who broker in immigration documents are legal residents or citizens of the United States. Immigration fraud is generally grouped into two types—immigration-related document fraud and immigration benefit/qualification fraud. Immigration-related document fraud includes the counterfeiting, sale, and/or use of identity documents or "breeder documents" (i.e., documents used to confirm identity, such as birth certificates or Social Security cards), as well as alien registration documents and stamps, employment authorizations, passports, visas, or any documents used to circumvent immigration laws. Benefit/qualification fraud encompasses the willful misrepresentation of a material fact to qualify for a status or benefit under immigration law in the absence of lawful eligibility for that benefit. Examples of benefit fraud include entering into a sham marriage in order to claim to be the spouse of a U.S. citizen; omitting a disqualifying criminal conviction from a petition to become an LPR; or falsely claiming to have been living in the United States continuously for the requisite time required for naturalization. Some view immigration fraud as a continuum of events because people may commit document fraud en route to benefit/qualification fraud. It is also presented as two overlapping concentric circles, as in Figure 1 , because there is considerable overlap in the crimes. The INA addresses immigration fraud in several ways. First, the law makes "misrepresentation" (e.g., obtaining a visa by falsely representing a material fact or entering the United States by falsely claiming U.S. citizenship) a ground for inadmissibility. Secondly, the INA has civil enforcement provisions, distinct from removal or inadmissibility proceedings, for individuals and entities proven to have engaged in immigration document fraud. Immigration fraud for purposes other than admission or an immigration benefit may nonetheless trigger other violations of immigration law, such a crimes of moral turpitude. In addition to the INA, §1546 of Title 18 of the U.S. Criminal Code makes it a criminal offense for a person to knowingly produce, use, or facilitate the production or use of fraudulent immigration documents such as visas, border crossing cards, and other documents covered by immigration-related statute or regulation. The U.S. Criminal Code furthermore criminalizes immigration fraud pertaining to the knowing falsification of naturalization, citizenship, or alien registry. More generally, the U.S. Criminal Code criminalizes the knowing commission of fraud in connection with a wide range of identification documents. Fraud-based activity may also be penalized under criminal statutes that generally bar fraudulent activity against the United States. The types of fraud investigations range in circumstances and scope. Many investigations focus on facilitators (i.e., individuals who sell, distribute, or manufacture counterfeit or altered documents), and on organized crime syndicates that broker large-scale illegal schemes such as sham marriage rings or bogus job offers. Investigations of immigration benefit applications are another major activity. For many years, the Immigration and Naturalization Service (INS) collected data measuring its workload in a system, known as the Performance Analysis System (PAS). The PAS compiled data on agent work hours for each of the major INS enforcement activities. In this report, the hours are aggregated into workyears. As immigration enforcement strategies changed and resources shifted over time, it has become evident that investigations of immigration fraud have declined as a priority ( Figure 2 ). In FY1986, for example, the productive workyears devoted to fraud investigation reportedly equaled the time of 256 special agents, and 11,316 fraud cases were completed. Ten years later (FY1995), there were the equivalent of 181 special agent workyears, and 6,455 cases were completed. When the INS issued its "Interior Enforcement Strategy" in 1999, minimizing immigration benefit fraud and other document abuse was listed as the fourth among the five top priorities. Evaluations of the government's efforts to combat immigration benefit fraud and document abuse have generally been critical. In 2003, the U.S. Government Accountability Office (GAO) noted that "INS did not believe it had sufficient staff to reach its program goals." GAO also reported that benefit fraud investigations were hampered by a lack of integrated information systems. "The operations units at the four INS service centers that investigate benefit fraud operate different information systems that did not interface with each other or with the units that investigate benefit fraud at INS district offices.... Thus, INS was not in the best position to review numerous applications and detect patterns, trends, and potential schemes for benefit fraud." As Figure 3 further illustrates, fraud investigations declined overall from FY1992 through FY2003 in terms of actual workyears. FY2003 was the last year these data were available. Although there was an upturn, most likely due to the 1999 Interior Enforcement Strategy previously mentioned, the trends over the decade were downward. As a percent of interior enforcement workyears, fraud investigations dropped from 14.1% in FY1992 to 7.0% in FY2003. Actual workyears fell from 264 to 175 over the same period. The cuts in fraud investigations from FY1992 through FY2003 appear to have been generally across the board in terms of types of investigations pursued. CRS data analysis indicates that workyears spent investigating facilitators of counterfeit or altered documents, organizations that broker large-scale illegal schemes and persons suspected of immigration benefit fraud have all decreased over this time period. Successful prosecutions of fraud cases likewise declined from 494 convictions in FY1992 to 250 convictions in FY2003. These data tracked the performance of the former INS, which the Homeland Security Act of 2002 ( P.L.107-296 ) abolished. As it established the Department of Homeland Security (DHS) in 2003, the Administration stated that Immigration and Customs Enforcement (ICE) would comprise the interior enforcement functions of the former INS, including the detention and removal program, the intelligence program, and the investigations program, along with the former U.S. Customs Service interior enforcement activities. While it was clear that ICE assumed responsibility for investigating immigration-related document fraud, it was less apparent whether ICE or another newly-created DHS bureau—the U.S. Citizenship and Immigration Services (USCIS)—had lead responsibility for investigating immigration benefit/qualification fraud. In 2006, ICE issued a press release that reported a marked increase in investigations and convictions in FY2004 and FY2005. "Criminal indictments in these cases have increased from 767 to 875, while arrests have risen from 1,300 to 1,391 and convictions have increased from 559 to 992." Subsequently, the DHS Office of Immigration Statistics (OIS) published different data, reporting that indictments rose from 709 in FY2004 to 1,065 in FY2005 and that convictions rose from 533 in FY2004 to 1,135 in FY2005. The most recent data published by OIS indicate that FY2006 paralleled FY2005, with 1,272 arrests, 1,032 indictments, and 1,073 convictions for identity and document fraud ( Figure 4 ). Because the FY2004 and FY2005 ICE document fraud data are derived from the Treasury Enforcement Control System (TECS) that was developed and used by the former U.S. Customs Service, it is not known how comparable these measures are to those based upon the FY1992-FY2003 PAS data. It is also not clear whether these document fraud indictments are unduplicated counts; that is, whether one case, for example, may be counted as immigration fraud as well as alien smuggling and human trafficking if the case was initiated as part of a human trafficking investigation and all three elements of the law are included in the arrest charges. In terms of cases prosecuted, the 2005 Syracuse University analysis of Department of Justice data reveal that immigration document fraud formed the basis for about 5% of the 37,765 immigration cases that DHS referred for prosecution in FY2004. This reported 5% referral rate is similar to the percentages depicted above in Figure 2 and Figure 3 for the percentage of interior enforcement workyears allocated to fraud investigations (7.0%) and the percentage of successful immigration fraud prosecutions (4.1%). As noted earlier, immigration fraud is a basis for inadmissibility and removal. Foreign nationals who are suspected of presenting fraudulent documents during inspection by a CBP officer at a port of entry are immediately put into removal proceedings, known as expedited removal.