The Aviation and Transportation Security Act established TSA as the federal agency with primary responsibility for securing the nation’s civil aviation system, which includes the screening of all passenger and property transported by commercial passenger aircraft. TSA currently has direct responsibility for, or oversees the performance of, security operations at approximately 457 TSA-regulated airports in the United States implementing security requirements in accordance with TSA- approved security programs and other TSA direction. At TSA-regulated airports, prior to boarding an aircraft, all passengers, their accessible property, and their checked baggage are screened pursuant to TSA- established procedures, which include, for example, passengers passing through security checkpoints where they and their identification documents are checked by TSOs and Travel Document Checkers, or by Screening Partnership Program employees. TSA uses multiple layers of security to deter, detect, and disrupt persons posing a potential risk to aviation security. These layers include three principal types of screening employees at airport checkpoints—Travel Document Checkers, who examine tickets, passports, and other forms of identification; TSOs, who examine property, including checked baggage, and persons using x-ray equipment and magnetometers, as well as other devices; and BDOs, using SPOT to assess passenger behaviors and appearance. BDOs are the only type of TSA screening employees not deployed to all TSA-regulated airports and all checkpoints within the airports where it is deployed on a regular basis. TSA deployed SPOT as an added layer of security to help deter terrorists attempting to exploit TSA’s focus on prohibited items and other potential security weaknesses. Other security layers cited by TSA include intelligence gathering and analysis; passenger prescreening; random canine team searches at airports; federal air marshals; reinforced cockpit doors; federal flight deck officers; the passengers themselves; as well as other measures both visible and invisible to the public. Figure 1 shows TSA’s 20 aviation security layers. The grey area in figure 1 highlights four layers that apply to passengers and their property as they seek to board an aircraft. Airport LEOs, another layer of security cited by TSA, do not report to TSA and may not maintain a physical presence at smaller TSA-regulated airports. According to TSA, each one of these layers alone is capable of stopping a terrorist attack. In combination, TSA states that their security value is multiplied, creating a much stronger system, and that a terrorist who has to overcome multiple security layers in order to carry out an attack is more likely to be preempted, deterred, or to fail during the attempt. The SPOT program utilizes behavior observation and analysis techniques to identify potentially high-risk passengers. Individuals who exhibit suspicious behaviors, including both physical and appearance indicators, may be required to undergo additional screening. Field agents and law enforcement officers of other federal agencies and entities—such as the FBI, the Secret Service, CBP, and FAMS—utilize elements of behavior detection analysis as a part of their work. In addition, some foreign entities, such as Israel’s El Al airlines, use behavior detection and analysis techniques as part of their security efforts. However, TSA emphasized to us that the SPOT program is unique among these entities because it uses a point system to help identify suspicious persons on the basis of their behavior and appearance and because behavior detection and analysis are the central focus of SPOT. Officials from the other agencies stated that their field personnel incorporate behavior detection as one of many skills used in their work; in contrast, behavior detection is the primary element of the BDOs’ work. SPOT trains BDOs to look for and recognize facial expressions, body language, and appearance that indicate the possibility that an individual is engaged in some form of deception and fears discovery. These behaviors and appearances are listed on a SPOT score sheet used in SPOT training. Passenger behavior and appearance are to be compared by the BDOs— who typically work in two-person teams. BDOs are expected to “walk the line”—that is, to initiate casual conversations with passengers waiting in line, particularly if their observations led them to question someone exhibiting behaviors or appearances on the SPOT checklist. As the BDOs walk the line, and the passenger with SPOT indicators is reached, a casual conversation is used to determine if there is a basis for observed behaviors or appearances on the checklist. In most instances, these conversations provide information to the BDOs that permits them to consider the issue resolved, and hence not a security concern. Figure 2 below illustrates the first step of the three-step SPOT process, the BDO-passenger interaction at a checkpoint prior to the passenger passing through a magnetometer. As shown in figure 2, passenger behavior and appearance are observed by the BDOs as passengers wait in line for screening at a security checkpoint. Even if the checkpoint is busy, the BDOs must attempt to visually scan all the passengers waiting in line, as well as persons near the checkpoint, to determine if any are showing behaviors or appearances on the SPOT checklist. According to TSA, on average a BDO has approximately 30 seconds to assess each passenger while the passenger waits in line. For passengers exhibiting indicators above baseline conditions, the BDOs are to (mentally) add up the points assigned to each indicator they observe. Both BDO team members must agree that observed indicators have exceeded the predetermined numerical threshold, although they do not have to identify the same indicators the passenger exhibited. In instances when a passenger’s SPOT indicators place them above the numerical threshold, and the passenger has placed their property on the conveyor belt for x-raying, and has walked through the magnetometer or equivalent screening device for passengers, he or she will be directed to the second step of SPOT, referral screening. This involves additional questioning and physical search of their person and property by BDOs and TSOs. This referral screening occurs in the checkpoint area. If the passenger’s behavior escalates further—accumulating more points based on the SPOT checklist—the BDOs are to refer the passenger to a LEO. A referral to a LEO is a potential third step in the SPOT process. BDOs are not LEOs—they do not conduct criminal investigations, carry weapons, or make arrests. After a passenger has been referred by the BDOs to a LEO, the LEO is then expected to independently determine, through additional investigation, such as questioning the passenger and, if appropriate, by conducting an identity verification and background check through the FBI’s National Crime Information Center (NCIC), whether sufficient grounds exist to take further action, such as detaining or arresting the passenger. TSA officials who are LEOs also have access to NCIC, such as an airport’s Assistant Federal Security Director for Law Enforcement or federal air marshals. NCIC is the FBI’s computerized index of criminal justice information (i.e., criminal record history information, fugitives, stolen properties, and missing persons), available to federal, state, and local law enforcement and other criminal justice agencies at all times. Similarly, other federal LEOs also have such access, including CBP, and Drug Enforcement Agency (DEA) personnel. However, since both local and federal LEOs have other responsibilities, and may not be present at each operating checkpoint, BDOs may have to seek them out to request an NCIC check. According to TSA, aside from requiring that an airport maintain a law enforcement presence, it exercises no jurisdiction over the law enforcement activities of non-TSA officers or entities at an airport; thus, it cannot require LEOs to conduct an NCIC check or to provide BDOs with information about the ultimate disposition of cases referred by them to LEOs. Once the LEO concludes his or her investigation and determines whether the passenger will be arrested or detained, TSA officials are to evaluate the security concerns to determine whether to allow the passenger to proceed to the boarding gate. (In some instances, a LEO might choose not to arrest or detain a passenger; TSA would then decide whether the infraction was sufficiently serious to necessitate barring the passenger from boarding.) After a referral incident has been resolved, BDOs are to enter information about the incident into TSA’s SPOT referral database. The data entered are to include time, date, location of the incident, behaviors witnessed, prohibited items found (if any), and information on the LEO’s response (if applicable), such as whether the LEO questioned the passenger, arrested the individual, or released the passenger. The SPOT referral database contains no personal identifying information about passengers. The SPOT program began with pilot tests in 2003 and 2004 at several New England airports, in which TSA began using uniformed BDOs at airport checkpoints. After some initial pilot projects and test deployments, 644 BDOs were deployed to 42 airports in the first phase of the program from November 2006 through June 2007. As of March 2010, about 3,000 BDOs utilizing SPOT were deployed at 161 of 457 TSA-regulated airports. BDO eligibility is restricted to TSOs with at least 12 months of TSO experience, or others with related security experience. Applicants must apply and be accepted into the BDO training program. The training includes 4 days of classroom courses, followed by 3 days of on-the-job training. BDOs must memorize all of the behaviors and appearances on the SPOT checklist, as well as the point value assigned to each, in order to be able to add these up to determine if a passenger should be sent to SPOT referral screening. BDO applicants must also pass a job knowledge test at the conclusion of the training. The test includes related multiple choice questions, true or false statements, and case-based scenarios.