Fact-checked by Grok 2 weeks ago

Unsub

Unsub, short for "unknown subject" or "unidentified subject," is a term originating in to refer to a in a whose identity remains unknown to investigators. The is commonly used by the (FBI) and other agencies during active cases involving suspects, such as serial offenders or perpetrators of unsolved violent crimes. The term appears in official FBI report s as "UNSUB" for unknown subject. The term dates back to at least the mid-20th century in FBI practices, with first known use in 1965. It was later popularized by FBI profilers such as John Douglas and , who helped formalize criminal behavioral analysis in the and . In professional contexts, "unsub" facilitates concise communication in reports, briefings, and operations, avoiding the need to repeatedly describe an anonymous individual while emphasizing the ongoing pursuit of identification. It is distinct from other investigative descriptors, such as "" or "," by specifically highlighting the lack of positive identification. Unsub gained widespread cultural recognition through American media, particularly crime procedurals that dramatize FBI operations. The 1989 NBC television series Unsub featured an elite forensics team hunting unidentified criminals, helping to introduce the term to broader audiences and influencing the genre's focus on psychological . Subsequent shows like (2005–2020) routinely employed "unsub" to denote the episode's , embedding it in popular despite some procedural inaccuracies in real-world applications. This media portrayal has occasionally led to public misconceptions about the term's exclusivity to the FBI or its routine use in every investigation.

Definition and Usage

Etymology and Meaning

"Unsub" is an informal term used in U.S. to refer to an unidentified or perpetrator in a . It serves as shorthand for describing the unknown individual responsible for a when their has not yet been established. The term is an for "unknown " or, alternatively, "unidentified ," reflecting its origins in the concise language of investigative reporting. It emerged as a practical way to denote suspects without known names in official documents and discussions within agencies like the FBI. Etymologically, "unsub" derives from the shorthand notation in reports, with its first documented use appearing in 1965. In usage, "unsub" is typically pronounced as "un-sub" (/ˈən-ˌsəb/), and it may appear in all caps as "UNSUB" in formal reports or documents to emphasize its acronym status. While primarily an oral and written term, it remains confined to professional contexts within American .

Application in Criminal Investigations

In criminal investigations, the term "unsub," an abbreviation for "unknown subject," serves a procedural role in denoting unidentified individuals suspected of involvement in crimes, particularly when no name or specific is available. This usage appears routinely in FBI case files, operational briefings, investigative reports, and inter-agency communications to maintain neutrality and avoid premature assumptions about guilt or . By employing "unsub," investigators can document and discuss suspects objectively, facilitating coordinated efforts without biasing the narrative toward unverified details. The term is most prevalent in contexts involving serial crimes, violent offenses such as homicides or sexual assaults, and operations within the FBI's (BAU) or similar forensic programs. For example, in the National DNA Index System (NDIS), "unsub cases" refer to unsolved investigations where DNA evidence from crime scenes is linked to an unknown perpetrator, enabling automated searches across databases to generate leads. Similarly, in the Violent Criminal Apprehension Program (VICAP), "unsub" helps narrow investigative focus on unidentified offenders exhibiting patterns across multiple incidents, supporting search warrants and collaborations. This application ensures consistent terminology in high-stakes environments where rapid, precise communication is essential. In legal and analytical documentation, "unsub" integrates into affidavits, profiles, and warrants to describe actions or characteristics without personalization. For instance, in affidavits supporting or search warrants, multiple unknown subjects may be designated as "UNSUB-1," "UNSUB-2," and so on, to detail their observed behaviors in events like coordinated criminal acts. In behavioral profiles, phrases such as "The unsub displays organized offender characteristics, including premeditation and control over the " guide investigative strategies by outlining likely traits based on patterns, aiding in suspect prioritization and resource allocation. These examples underscore "unsub's" role in promoting evidentiary rigor and collaborative objectivity across documentation.

History and Development

Origins in Law Enforcement

The term "unsub," short for "unknown subject," emerged as informal shorthand within U.S. law enforcement during the mid-20th century, predating formalized criminal profiling techniques. Its roots trace to the post-World War II era, when rising crime rates prompted increased use of abbreviated jargon in investigative reporting to denote unidentified perpetrators in unsolved cases. This period saw a notable surge in violent crime, with rates climbing from relatively low levels in the 1950s to dramatic increases by the 1960s, straining local police resources and encouraging concise documentation practices. Early uses of the full phrase "unknown subject" appear in and reports from the late and , reflecting a need for efficient language in handling anonymous offenders amid growing caseloads. For instance, a 1950 edition of the FBI Bulletin described an involving "the unknown subject," highlighting its application in routine narratives for unidentified individuals suspected in crimes like assaults. By the early , this terminology was documented in investigative memos and case files, such as a 1960 Department of report on a civil rights incident in , where the perpetrator was labeled an "unknown subject." The abbreviation "unsub" had its first known use by 1965. These appearances in archives underscore the term's practical adoption for streamlining reports on unsolved incidents. Local police departments in high-crime areas were early adopters of shorthand for unidentified suspects by the late 1950s, driven by overwhelming volumes of anonymous crime reports, though the specific term "unsub" became more associated with federal agencies.

Evolution in FBI Profiling

The term "unsub," denoting an unknown subject, was adopted within the FBI's Behavioral Science Unit (BSU)—later renamed the Behavioral Analysis Unit (BAU)—during the 1970s as criminal profiling emerged as a formal discipline. Established in 1972 at the FBI Academy in Quantico, Virginia, the BSU focused on applying psychological insights to violent crimes, with pioneers Robert Ressler and John E. Douglas instrumental in its development. Ressler joined the unit in 1975, and Douglas transferred to the BSU in 1977; they collaborated on early offender interviews and profile development during this foundational period. The 1970s and 1980s marked key milestones in the term's expansion, coinciding with heightened FBI involvement in investigations amid a surge in such cases across the . The BSU's profiling efforts, including assessments of offender and signature behaviors for unsubs in multi-victim crimes, gained prominence through cases analogous to those of , where the term aided in linking disparate incidents without premature suspect identification. This period saw the unit conduct extensive interviews with incarcerated offenders to refine unsub profiles, culminating in the establishment of the National Center for the Analysis of Violent Crime (NCAVC) to coordinate behavioral research and support. The 1985 launch of the Violent Criminal Apprehension Program (VICAP) under NCAVC further integrated "unsub" by enabling nationwide data collection on subjects, streamlining searches during active serial investigations. By the 1990s, "unsub" had achieved institutional standardization within FBI training academies and the NCAVC, serving as core terminology in behavioral analysis curricula and operational protocols. The 1992 Crime Classification Manual, authored by Douglas, Ressler, and colleagues, codified its use across categories—such as , , and —providing a framework for classifying unsub actions based on indicators. This became a cornerstone of instruction, ensuring consistent application in profile development and case consultations. The term's role in FBI profoundly impacted criminal investigations by enabling unbiased assessments of unsubs through of behavioral , such as organized versus disorganized offender traits. This approach, emphasizing dynamics over suspect demographics, reduced identity-related biases and enhanced predictive accuracy in narrowing suspect pools, as demonstrated in NCAVC-supported cases throughout the decade.

Portrayal in Media

Television Series and Shows

The term "unsub" received its first major exposure in television through the NBC series Unsub, which premiered on February 3, 1989, and ran for eight episodes until April 14, 1989. Created by , David J. Burke, and Stephen Kronish, the show followed an elite FBI forensic team specializing in behavioral science to track serial offenders, marking an early dramatization of investigative jargon in procedural dramas. The term achieved widespread prominence in the series , which originally aired from 2005 to 2020 across 15 seasons and 324 s, and its revival (2022–present), portraying the FBI's (BAU) as they profile and pursue "unsubs"—unknown subjects responsible for crimes. In the series, "unsub" serves as core terminology for unidentified perpetrators, often detailed through team briefings and psychological analyses, embedding the deeply into the show's narrative structure. The program averaged around 13 million viewers per during its peak seasons, contributing significantly to the term's normalization in mainstream discourse. Brief appearances of "unsub" occur in other series, such as Netflix's Mindhunter (2017–2019), where FBI agents developing criminal profiling in the late 1970s reference it sporadically, including in season 1's finale when discussing the case, reflecting real FBI methodologies. These portrayals, drawing from historical FBI practices, helped elevate "unsub" from specialized lingo to a recognizable element of public lexicon through procedural television. Overall, shows like Unsub and transformed the term by integrating it into high-viewership narratives, with alone reaching over 10 million viewers per season on average, fostering broader cultural familiarity beyond professional contexts. The revival continues this tradition, with the BAU tackling complex unsub cases in modern settings, maintaining the term's prominence in the genre as of 2025.

Literature and Other Media

In thriller novels, the term "unsub," shorthand for unknown subject, has been prominently featured to denote unidentified perpetrators in criminal investigations. Meg Gardiner's 2017 novel Unsub, the first installment in her UNSUB series, centers on narcotics detective Caitlin Hendrix, who joins a homicide task force to pursue a serial killer dubbed the Prophet, inspired by the Zodiac Killer's cryptic communications and ritualistic murders. The narrative draws on FBI behavioral analysis techniques, with the unsub representing a elusive figure who taunted law enforcement a decade earlier, forcing Hendrix to confront her father's failed pursuit of the same killer. Subsequent books in the series, such as Into the Black Nowhere (2018), continue this theme by depicting Hendrix's FBI role in tracking an unsub modeled after Ted Bundy, emphasizing psychological profiling and the personal toll of the hunt. Patricia Cornwell's long-running Scarpetta series, beginning with Postmortem (1990), explores analogous concepts through forensic pathologist Kay Scarpetta's encounters with unidentified killers in detailed medical examinations and investigations, often involving FBI collaboration on cases that highlight the challenges of anonymous suspects. While the series predates widespread popularization of the term "unsub," its procedural focus on elusive criminals has influenced modern thrillers incorporating similar . In films and documentaries, the unsub concept appears in portrayals of hunts, as seen in the 1991 adaptation of Thomas Harris's , where FBI trainee profiles the unidentified "," an unsub-like figure who skins victims to construct a suit from human hides, relying on insights from incarcerated cannibal . True-crime documentaries from the , such as episodes of Investigation Discovery's Mind of a Monster series, delve into the psychology of anonymous killers through expert analysis, echoing unsub profiling by reconstructing the mindset of perpetrators like the Green River Killer without revealing their identities until late in the narrative. Video games have integrated unsub-style suspect profiling into interactive narratives, notably in Quantic Dream's (2010), where players control FBI agent Norman Jayden, who uses an interface to analyze crime scenes and build a profile of the Killer, an unidentified serial murderer drowning young boys during rainstorms. The game's branching storylines emphasize to narrow down suspects, mirroring real-time unsub identification in behavioral science. True-crime podcasts have amplified the term's resonance in audio formats, with (2014) hosted by examining the 1999 murder of and the profiling of her ex-boyfriend Adnan Syed as a potential unsub, using journalistic to question and evidentiary gaps in a manner that parallels FBI casework. By the , the term "unsub" had permeated broader cultural expressions beyond traditional media, appearing frequently in communities and online discussion forums dedicated to crime genres, where writers and enthusiasts repurpose it to describe anonymous antagonists in user-generated stories inspired by procedural fiction. This spread reflects the term's adoption in amateur narratives exploring psychological thrillers and investigations. The popularity of "unsub" in these spaces can be traced back to its earlier amplification through television procedurals.

Related Concepts

Distinctions from Similar Terms

In FBI investigations, the term "unsub," an abbreviation for "unknown subject," specifically denotes the unidentified individual believed to have committed a crime, emphasizing the lack of established identity or direct evidentiary links. This contrasts with a "," which typically refers to a known person for whom there exists or based on available , allowing for targeted investigative actions such as or . While both terms relate to potential offenders, "unsub" highlights the phase of , where behavioral analysis is used to develop characteristics rather than pursue a named individual. Unlike a "" (POI), which is a broader, often public-facing designation for individuals—known or unknown—who may possess relevant information or tangential involvement without implying direct culpability, "unsub" serves as a more precise, internal term among FBI profilers for the primary unknown offender in violent or cases. The POI label is designed to be less accusatory, facilitating cooperation from witnesses or associates while minimizing legal exposure in media releases, whereas "unsub" remains confined to operational discussions within the to focus on predictive modeling of the offender's actions. The "unsub" designation also differs from "perpetrator," a term reserved for the confirmed actor in a , typically applied after , , or when guilt is substantiated through or judicial process. In contrast, "unsub" is employed pre- to maintain investigative neutrality, avoiding assumptions of guilt. This semantic choice aligns with FBI guidelines in criminal and reporting, where neutral language like "unsub" prevents premature attribution that could lead to legal challenges, such as claims or compromised case integrity, by focusing on behavioral patterns rather than personal identifiers.

Modern Usage and Variations

In the digital age, the term "unsub" has expanded beyond traditional physical crimes to encompass investigations, particularly since the , where hackers and perpetrators of online attacks are profiled as "digital unsubs." For instance, the FBI employed an "unsub" investigation in a 2017 case involving a CIA hacker's alleged plot through intrusions, highlighting how the designation aids in tracing digital footprints when identities remain obscured. This usage continues in recent and state-sponsored threat probes as of 2025, with the FBI applying "unsub" profiling in operations targeting unidentified actors in incidents like the 2024 breach. Internationally, adoption of "unknown subject" has been limited but influenced by U.S. media exports, appearing in and Canadian policing contexts for unidentified individuals in and investigations. In the , use the term in facial recognition operations, where "probe images" of unknown subjects are scanned against watchlists to identify suspects in public spaces. Canadian has referenced an "unknown subject" in contexts involving suspicious activities, reflecting cross-border terminological borrowing amid shared . This usage remains niche, often tied to collaborative efforts with U.S. agencies rather than native . Variations of the term persist in academic , where "unidentified offender" serves as a more formal equivalent, emphasizing behavioral and linkage in unknown perpetrators. Scholars describe constructing profiles of unidentified offenders through evidence collection, , and statistical modeling to narrow pools, as seen in studies on offenses. Critiques highlight how media overuse of "unsub"-like portrayals fosters public misconceptions, such as overestimating 's accuracy; shows heavy viewers of fictional shows exhibit stronger beliefs in its utility (86.1% acceptance rate) and (58.5% belief in accuracy), potentially skewing societal expectations of investigations. Current FBI data from the 2020s indicates that unsub designations apply to a substantial portion of violent cases, with uncleared rates—reflecting unknown offenders—averaging around 55% in 2020 and 50% in 2022 for reported violent offenses, underscoring ongoing challenges in identification despite technological advances (as of FBI data released in 2023).

References

  1. [1]
    UNSUB Definition & Meaning - Merriam-Webster
    The meaning of UNSUB is the unknown perpetrator of a crime. How to use unsub in a sentence.
  2. [2]
    Law enforcement jargon every police officer should know - Police1
    Jun 13, 2024 · Unsub: FBI term for “unknown subject/suspect,” a person of interest whose identity is unknown; UTL: Radio code for “unable to locate”. V. Vest ...<|control11|><|separator|>
  3. [3]
    Unsub: Understanding Its Legal Definition and Implications
    "Unsub" is short for "unknown subject." It is used in investigations to refer to an individual whose identity is not known to law enforcement or investigators.
  4. [4]
    What is the FBI definition of 'unsub' or is it only a TV word? - Quora
    Jun 11, 2019 · An "unsub" is an unknown subject or unsubstantiated lead in an FBI investigation. The term is used by real FBI agents, and it is short for " ...Is unsub a term used in real world? - QuoraDoes the FBI use the word unsub? - QuoraMore results from www.quora.com
  5. [5]
    Is unsub a real law enforcement term? - Facebook
    Aug 29, 2025 · It's real. John Douglas and Robert ressler who were the real life founders of profiling used the term and popularized it.In the mindf*ck series by Stabby, what does unsub mean? It's driving ...Unsub American TV series on NBC 1989 - FacebookMore results from www.facebook.com
  6. [6]
    'UNSUB' Is Mostly Forgotten, But It Launched a New Era of Crime ...
    Dec 11, 2023 · If “UNSUB” had been a typical Stephen J. Cannell hit, perhaps the phrase “CSI effect” might have been “UNSUB effect” instead.Missing: origin term
  7. [7]
    5 Things Criminal Minds Got Wrong About Criminal Profiling (& 5 It ...
    Jun 21, 2024 · "UNSUB" Is A Real FBI Term​​ While the methods of the BAU in Criminal Minds may not be accurate, much of the terminology they use is true to real ...
  8. [8]
    UNSUB Definition & Meaning - Dictionary.com
    a suspect in a crime investigation whose identity or name is not known. unsub. 3.
  9. [9]
    12. Abbreviations Used In FBI Reports - Department of Justice
    Abbreviations Used In FBI Reports: AD - Assistant Director, ADIC - Assistant Director in Charge, AGO - Adjutant General's Office, AKA - Also Known As, CID - ...<|control11|><|separator|>
  10. [10]
    [PDF] National DNA Index System (NDIS) Operational Procedures Manual
    Standard 11 of the FBI's QAS requires confidentiality for reports, case files, DNA ... An unsolved case is equivalent to 'No suspect case' and 'Unsub case'.
  11. [11]
    The Birth of Modern Day Criminal Profiling | Psychology Today
    May 26, 2015 · More specifically, VICAP was designed to aid investigators in narrowing the search for an unknown subject (or “Unsub” in FBI terminology) and ...
  12. [12]
    Criminal Investigative Analysis: Practitioner Perspectives (Part ... - LEB
    Jun 10, 2014 · Experts within the FBI's Behavioral Science Unit (BSU) initiated the practice of profiling, which involves providing a requesting department ...Missing: avoid | Show results with:avoid
  13. [13]
    First Measured Century: Interview: Elliot Currie - PBS
    ELIOTT CURRIE: Crime rates went up very dramatically in the 1960s. They had been quite low during the Second World War, during the 1950s and up through the ...
  14. [14]
    History of Crime and Punishment in America: 1950–1970
    The violent crime rate rose from 160.9 per 100,000 in 1960 to 363.5 per 100,000 in 1970. Over this 10-year period, the murder rate increased ...
  15. [15]
    [PDF] • Restricted to the Use of Law Enforcement Officials - LEB
    A sailor whose general description fitted that of the unknown subject was taken into custody but the victim was unable to make a positive iden- tification. At ...
  16. [16]
    Fred Robinson - Notice to Close File - Department of Justice
    Apr 18, 2023 · Re: Unknown Subject Edisto Island, SC – Subject; Fred Robinson ... Police Report. At about 4 p.m. on August 3, 1960, CCPD XXXXXX and ...
  17. [17]
    List of Espionage Terms | Dr. Hugh Fox III
    UNSUB – An unknown subject in a surveillance operation. VCP – Vehicle Control Point. Walk-in – A defector who declares his or her intentions by walking into an ...
  18. [18]
    [PDF] Untitled - GovInfo
    UNKNOWN SUBJECT; MICKEY MANTLE -. VICTIM. CHARACTER OF CASE. Approved. Copies made: REFERENCES. EXTORTION. Investigativa Pustod. 7/20/60 - 9/29/60. Typed By maf.
  19. [19]
    [PDF] docid-32572439.pdf - National Archives
    Note, numbers 1 and 2 are a dual caption. UNKNOWN SUBJECT; Theft of $70,000 in Diamond Rings from. HAROLD KLEIN, Salesman, M. W. Schiffman Company, New York.<|control11|><|separator|>
  20. [20]
    Serial Killers, Part 2: The Birth of Behavioral Analysis in the FBI
    Oct 23, 2013 · In 1972, the FBI stood up a behavioral science unit to advance the concepts the pair was teaching throughout the FBI and across law enforcement ...
  21. [21]
    THE F.B.I.'S NEW PSYCHE SQUAD - The New York Times
    Oct 26, 1986 · ... police term for Unknown Subject, was either a transient serial killer or perhaps some recently released mental patient. Only after two ...
  22. [22]
    [PDF] Crime Classification Manual
    Jun 22, 1995 · ... Behavior reflects personality. Everything observed at a crime scene tells a story and reflects something about the unknown subject (UNSUB) ...
  23. [23]
    Criminal Investigative Analysis: Skills, Expertise, and ... - LEB - FBI
    Jul 8, 2014 · Historically, the criminal investigative approach stems from the original process developed by the FBI's Behavioral Science Unit (BSU) in the ...
  24. [24]
    Unsub (TV Series 1989) - IMDb
    Rating 8/10 (180) A special team of FBI forensics experts investigates serial murderers and other unsolved violent crimes.
  25. [25]
    Unsub - TheTVDB.com
    Unsub is an American television series that aired on NBC from February 3 to April 14, 1989. The series centers around an elite FBI forensic team.
  26. [26]
    Criminal Minds: 2011-2012 TV Season Ratings
    Season average: 3.48 in the demo with 12.79 million. Demo average rank: #7 of 21 scripted TV shows on the network (Fall 2011 – Spring 2012). UPDATE: Criminal ...
  27. [27]
    'Mindhunter' Goes Back To The Start Of Serial Killer Stories - UPROXX
    Oct 17, 2017 · Uproxx TV critic Alan Sepinwall reviews 'Mindhunter,' a new Netflix series that goes back to the beginning of modern serial killer stories.
  28. [28]
    UNSUB by Meg Gardiner: 9781101985540 - Penguin Random House
    “Like The Silence of the Lambs, this novel scared the hell out of me. I dare you to try putting it down. The UNSUB, or unknown subject, at the heart of Meg ...<|separator|>
  29. [29]
    The Silence of the Lambs (1991) - IMDb
    Rating 8.6/10 (1,676,572) A young FBI cadet must receive the help of an incarcerated and manipulative cannibal killer to help catch another serial killer, a madman who skins his victims.Full cast & crew · Trivia · Thomas Harris · The Silence of the LambsMissing: unsub | Show results with:unsub
  30. [30]
    Chapter 3 - Crime Scene - Heavy Rain Guide - IGN
    Jul 11, 2018 · Press the R1 Button to scan the surroundings for clues, and then go up to them and follow more prompts to look at them. To earn the FBI ...
  31. [31]
    Episode 01: The Alibi - Serial Productions
    Hae Min Lee, a popular high-school senior, disappears after school one day. Six weeks later detectives arrest her classmate and ex-boyfriend, Adnan Syed, for ...
  32. [32]
    Unsub: BAU, a criminal minds fanfic | FanFiction
    May 1, 2010 · A rather mesmerizing picture of my countenance, capturing the exuberance and the likeness of my self. My former self, that is.
  33. [33]
    [PDF] TWISTED: Acronyms & Terms - Andrea Kane
    Unsub - Unknown Subject. Just as "perp" is police lingo for perpetrator, subject or offender is FBI lingo for the same. If the identity of the subject is.Missing: terminology | Show results with:terminology
  34. [34]
    [PDF] Wisdom begins with the definition of terms - DNI.gov
    Aug 15, 2007 · See FOUO definition in O-DoDD 5240.02, CI, 20 Dec 2007. DoD Unknown Subject. The subject of a DoD CI investigation whose identity has not ...
  35. [35]
    The Surreal Case of a C.I.A. Hacker's Revenge | The New Yorker
    Jun 6, 2022 · The Bureau was pursuing what it calls an “unsub”—or “unknown subject”—investigation. “A crime had been committed; we didn't yet know who had ...
  36. [36]
    SOLAR SUNRISE After 25 Years: Are We 25 Years Wiser?
    Feb 28, 2023 · This memo from the FBI's Albuquerque Field Office to the National Security Division/Criminal ... Federal Bureau of Investigation, "Unsub(s); ...
  37. [37]
    [PDF] Biometric Britain: The Expansion of Facial Recognition Surveillance
    May 23, 2023 · probe images [photos of the unknown subject] can be taken from anywhere as long as officers establish the source of the photograph, so they ...
  38. [38]
    Officers from North Patrol were recently called together for a briefing ...
    Feb 12, 2025 · An unknown subject has been frequent in police facilities in our region. He's often seen lurking in WRPS facility parking lots at various ...Missing: terminology | Show results with:terminology
  39. [39]
    Offender Profiling | LawTeacher.net
    Furthermore, Hicks & Sales (2006) stated that constructing a profile of an unidentified offender involves three stages; collecting evidence from a crime ...Missing: term | Show results with:term
  40. [40]
    Do We Mistake Fiction for Fact? Investigating Whether the ...
    Apr 18, 2022 · The present study is the first to investigate whether the perception of criminal profiling may be influenced by the consumption of fictional crime-related ...
  41. [41]
    Clearance Rates for Reported Violent and Property Crimes in the ...
    Clearance Rates in the US for Violent and Property Offenses Known to Police and Cleared by Arrest or Exceptional Means, 1996-2020 and 2022 Violent Crimes ...