In 1970, the K visa category was created for foreign national fiancé(e)s of U.S. citizens. The first visa within the category, the K-1 visa, is a nonimmigrant visa that grants temporary admission to the United States for fiancé(e)s in order for them to marry their U.S. citizen petitioners. Since the visa's creation, Congress has passed additional legislation that has added protections for fiancé(e)s and their children. There were 35,925 K-1 visas issued by the U.S. Department of State (DOS) in FY2014. The K-1 visa has drawn increased attention due to a mass shooting in San Bernardino, CA, on December 2, 2015. One of the suspected shooters, Tashneen Malik, reportedly came to the United States on a K-1 visa to marry the other suspected shooter, Syed Rizwan Farook. The investigation of the couple, after the fact, reportedly brought to light suspicions to the couple's support of violent jihadists. Due to these events, Congress and the public have raised questions about the K-1 visa and its security screening. For instance, how well are individuals screened for fraud and security risks, and are there any gaps in the screening process? After the shooting, President Barack Obama asked the U.S. Department of Homeland Security (DHS) to review the U.S. visa program. Some members of Congress have also called for the inclusion of visa applicants' social media accounts as an added screening measure. This report will review the K-1 visa, providing information on the background of the program. Next, the report will cover the requirements of the visa and its application procedures, including the filing of a petition, the application for a visa, and the national security screening. The following section will describe K-1 visa holders' admission to the United States and their adjustment of status to lawful permanent residency. The last section will provide statistics on the issuance of the K-1 visa and the source countries of visa holders. P.L. 91-225 established the K nonimmigrant visa category in 1970 for fiancés, fiancées, and the derivative children of the fiancé(e). The law amended the Immigration and Nationality Act (INA) in an effort to address the difficulties faced by U.S. citizens who wished to bring their fiancé(e)s to the United States to be married. There are four subcategories within the K visa category. P.L. 91-225 created the first two categories (K-1 visa and K-2 visa), and in 2000 the Legal Immigration Family Equity Act (LIFE Act; Title XI of P.L. 106-553 ) created the last two categories (K-3 visa and K-4 visa). The K-1 visa is for noncitizens seeking to enter the United States to marry a U.S. citizen, and the K-2 visa is for their children. The K-3 visa is for noncitizens who married a U.S. citizen abroad and want to enter the United States while they wait for their immigration petition, or for an immigrant visa to become available, and the K-4 visa is for their children. Subsequent legislation was enacted in order to provide protections to the fiancé(e) (also referred to as the beneficiary). The International Marriage Broker Regulation Act of 2005 (IMBRA; Title VIII, Subtitle D, of P.L. 109-162 ) requires the disclosure of the use of an international marriage broker and the petitioner's criminal convictions for certain crimes, notably sexual crimes. Additionally, IMBRA provides requirements with regard to international marriage brokers and requires the Department of State to provide beneficiaries with a pamphlet containing facts about the K-1 visa, domestic violence, and their rights. The Adam Walsh Child Protection and Safety Act of 2006 ( P.L. 109-248 ) further prohibits U.S. citizens from petitioning for a K-1 visa if they have been convicted of certain offenses against a minor (unless the Secretary of DHS can determine, under his/her sole discretion, that the petitioner poses no risk to the beneficiary). In order for a foreign national to be issued a K-1 visa, the petitioner who is filing on the fiancé(e)'s behalf must be a U.S. citizen and must provide the following evidence: The parties have met in person within two years of the petition's filing, though the Secretary of DHS may waive this requirement. The parties have a bona fide intention to marry. The parties are legally able and willing to conclude a valid marriage in the United States within 90 days of the fiancé(e)'s arrival. In addition to the determination that a foreign national is qualified for a K-1 visa, a decision must be made as to whether the foreign national is admissible or excludable under the INA. A U.S. citizen petitioner must file Form I-129F, Petition for Alien Fiancé(e), with DHS's U.S. Citizenship and Immigration Services (USCIS), along with supporting documents. Additional requirements, established in IMBRA, mandate that the petitioners provide criminal records related to certain crimes and that they notify USCIS if they used an international marriage broker to meet the beneficiary. IMBRA also requires the petitioners to obtain a waiver if they have filed two or more K-1 petitions in the past or have had a K-1 petition approved in the two years before their current petition. Furthermore, if the petitioners are subject to the Adam Walsh Child Protection and Safety Act, they must demonstrate they pose no risk to the beneficiary. After USCIS approves a petition, it is sent to the U.S. Embassy or Consulate in the home country of the foreign national to determine eligibility for a K-1 visa for admission to the United States. The petitioner and beneficiary (including eligible children) must provide a completed Form DS-160, Online Nonimmigrant Visa Application, valid passports, divorce or death certificates for any previous spouses, police certificates from their present countries of residence and other countries they lived in for at least six months, medical examinations, evidence of financial support, photographs, evidence of relationship, and fees. Once all necessary documents are provided and security clearances are completed, the consular office schedules an interview to determine eligibility. Although the K-1 visa is a nonimmigrant visa, due to the beneficiary's intention of remaining in the United States, the consular office treats it as an immigrant visa and seeks to determine whether the individual would be admissible as an immigrant. Additionally, DOS has issued instructions with regard to consideration of these applications. The K visa applicant is required to submit his or her photograph and fingerprints, as well as full name (and any other name used or by which he or she has been known), age, gender, and the date and place of birth, as are all foreign nationals seeking a visa. The visa applicant's personal data are added to the Consular Consolidated Database (CCD), a biometric/biographic database that screens all visa applicants, including those seeking a K visa. CCD links with other databases to flag problems that may have an impact on the issuance of the visa, which include DHS's Automated Biometric Identification System (IDENT) and the Federal Bureau of Investigation (FBI) Integrated Automated Fingerprint Identification System (IAFIS). In addition to performing biometric checks of the fingerprints for all visa applicants, DOS uses facial recognition technology to screen visa applicants against a "watchlist" of photos of known and suspected terrorists obtained from the Terrorist Screening Center (TSC), as well as the entire gallery of visa applicant photos contained in the CCD. To screen K visa applicants, as well as all other visa applicants, consular officers use the Consular Lookout and Support System (CLASS) database, which has name-searching algorithms to ensure matches between names of visa applicants and any derogatory information contained in CLASS. DOS reports that about 70% of the records in CLASS come from other agencies, including DHS, the FBI, and the Drug Enforcement Administration (DEA). DOS also employs an automated CLASS search algorithm that runs the names of all visa applicants against the CCD to check for any prior visa applications, refusals, or issuances. Consular officers have long relied on the Security Advisory Opinion (SAO) system, which requires a consular officer abroad to refer selected visa cases for greater review by intelligence and law enforcement agencies. If consular officials receive information about a K visa applicant that causes concern, they send a dedicated and secure communication to the National Counterterrorism Center (NCTC). In a similar set of SAO procedures, consular officers send suspect names, identified by law enforcement and intelligence information, to the FBI for a name check. There is also the "Terrorist Exclusion List" (TEL), which lists organizations designated as terrorist-supporting and includes the names of individuals associated with these organizations. In June 2013, DOS began "Kingfisher Expansion" (KFE) in partnership with the NCTC for conducting interagency counterterrorism screening of all visa applicants. The consular official submits the K visa applicants' electronic visa applications as a "vetting package" to the NCTC. In turn NCTC uses an automated process to compare the vetting package with its holdings, most notably the Terrorist Identities Datamart Environment (TIDE) on known and suspected terrorists and terrorist groups. A "hit" in KFE triggers a Washington-based interagency review of the visa application. KFE also conducts post-issuance reviews of valid visas to check for new information on emerging threats.