Comprehensive Study Notes on Criminal Investigation, History, and Forensic Science

Fundamentals of Criminal Investigation and Investigative Goals

  • Core Role of the Investigator

    • Gathers information, physical evidence, and documentation.
    • Primary objective: Determine the truth and verify the veracity of collected information, evidence, and documents through systematic investigative processes.
    • Core course textbook focus: Chapters 1, 2, and 22 (the judicial/court process, highlighted by legal instructional films like My Cousin Vinny).

  • Primary Goals of an Investigation

    • Establish if a crime was committed: This is the primary issue in any criminal inquiry.
    • Investigate unequivocal non-criminal incidents: Investigators handle fatal motor vehicle crashes and potential suicides to determine whether foul play occurred.
      • Example: An off-duty Camden County police officer struck and killed a pedestrian on Admiral Wilson Boulevard (the primary highway leading to the Ben Franklin Bridge). Inquiries evaluate whether the pedestrian intentionally walked into traffic to commit suicide.
    • Identify and apprehend suspects.
    • Recover stolen property and physical evidence.
    • Prepare cases for prosecution: Assist prosecuting attorneys throughout legal proceedings.
      • Duration: Complex cases ("career cases") can span decades.
      • Case Study (Mumia Abu-Jamal): Officer Faulkner was murdered in December 1981. The Philadelphia District Attorney, with the consent of the victim's spouse, police department, and the Fraternal Order of Police (FOP), agreed to remove the death penalty in exchange for a life sentence without appeal. Despite signing the agreement, Abu-Jamal appealed a year later. Over 40+ years, his underlying conviction has never been overturned; successful appeals related solely to the death penalty due to judicial resistance to capital punishment.
      • Capital Punishment Trends: In New Jersey, following the Supreme Court's reinstatement of the death penalty around 1970–1975, every death penalty sentence imposed was overturned by the state Supreme Court except for the Marshall case (where a husband hired three men from Louisiana to murder his wife); Marshall ultimately died in prison.

  • Essential Elements of Criminal Investigation

    • Witness Interviews: Requires refined interviewing techniques to evaluate witness perceptions of time and distance.
      • Perception Example: Witnesses frequently estimate brief events as lasting "five minutes" when the actual duration was only 5 to 30 seconds.
    • Physical Evidence and Searches: Crime scene processing, physical searches, and search warrants.
    • Admissions and Interrogations: All interrogations begin as non-accusatory interviews before transitioning into formal interrogations.

Legal Foundations, Jurisdiction, and Statutory Limits

  • Three Fundamental Questions for Law Enforcement

    1. Do I have authority?
    2. Do I have jurisdiction?
    3. Does the offense fall within the statute of limitations?

  • Jurisdictional Authority and Geography

    • Jurisdiction requires both statutory authority and geographical standing.
    • Geographical Boundaries Example: Transitioning along Cherry Tree Road near the tank farm crosses from Ashton Township into Upper Chichester Township. School district boundaries also intersect municipal lines (e.g., Northley Junior High and Sun Valley High School on Concord Road sit near Chester Township, whose students attend the Chester Upland School District).
    • Pennsylvania Municipal Police Jurisdiction Act (MPJA):
      • Grants territorial authority to municipal police officers.
      • An officer cannot formally charge an individual for an "on view" or probable cause crime that occurred outside their specific municipality unless statutory exceptions apply.
      • Mutual Aid Agreements: Allow municipal officers to act outside their primary border upon request or backup call from another jurisdiction's chief of police or designee.
      • Statewide Off-Duty/On-Duty Authority: Officers traveling across Pennsylvania on legitimate official business (e.g., a Delaware County detective traveling through Philadelphia) maintain arrest powers if they observe a crime in progress or possess immediate probable cause.
    • Federal Authority: Federal agencies (FBI, DEA, ATF) are strictly restricted to federal statutory offenses and interstate matters.
      • Federal Depository Insurance Corporation (FDIC): Makes bank robbery a federal crime.
      • Interstate Commerce: Motor vehicle theft becomes federal upon crossing state lines. Hijacking cargo trucks falls under federal jurisdiction due to interstate transportation laws.
      • Interstate Communications: Fraud or crimes executed via telephone, wire, or mail trigger federal jurisdiction.

  • Statute of Limitations

    • Determined legally by prosecutors and judges, not field investigators.
    • General Rule: 2 years for minor offenses; 5 years for major felonies in most jurisdictions.
    • Pennsylvania Specifics:
      • Homicide: No statute of limitations.
      • Child Physical/Sexual Abuse: The statute of limitations extends until the victim reaches 50 years of age (e.g., an offense occurring at age 12 can be reported up to age 49 years and 364 days).

Historical Evolution of Law Enforcement and Detective Agencies

  • Early European Foundations

    • Henry Fielding and the Bow Street Runners: In the 1740s–1780s, London Magistrate Henry Fielding organized court volunteers who ran or rode horses to crime scenes to gather evidence, founding the Bow Street Runners.
    • John Fielding: Succeeded his brother Henry; expanded the group's operational scope and established a central clearinghouse for criminal data.
    • Criminal Intelligence: Defined strictly as information that has been collated and analyzed.
    • Sir Robert Peel: Established the London Metropolitan Police in 1829. Officers were nicknamed "Bobbies" after him. His professional conduct guidelines and hiring criteria remain the standard for modern policing.

  • Development of American Policing

    • Stephen Girard: Philanthropist who established the short-lived (3-year) first daylight police force in Philadelphia, as well as Girard College (originally for white male orphans, integrated roughly 60–70 years ago).
    • Anti-Government Sentiment: Early Americans resisted centralized police forces due to fear of government tyranny following the American Revolution. In 1844, the New York Legislature established the first unified police department in the United States, followed by Chicago, New Orleans, Cincinnati, and Baltimore, all adopting Peel's model.

  • Allan Pinkerton and Private Detection

    • A Scottish immigrant and barrel maker (cooper) who solved crimes independently before briefly joining a municipal police force.
    • Resigned to found the Pinkerton National Detective Agency due to structural flaws in early public policing:
      1. High levels of municipal graft and corruption driven by low officer pay.
      2. Municipal and county sheriff jurisdictions were severely restricted geographically.
      3. Complete lack of intergovernmental law enforcement information sharing.
    • Information Sharing Failure Parallel: Prior to September 11, 2001, FBI field agents flagged foreign nationals enrolled in flight schools seeking to fly Boeing 747s without learning basic takeoffs or landings, but strict bureau administrative procedures prevented centralized intelligence collation in Washington.
    • Pinkerton Innovations and Characteristics:
      • Trademark: A large open eye with the slogan "We never sleep"—giving rise to the term "Private Eye."
      • Pioneering Practices: Employed undercover operatives and hired female detectives in the 1840s and 1850s.
      • Operational Reach: Unhampered by local borders, serving banks, railroads, and corporations through centralized reporting.
      • Reputational Decline: Diminished by anti-labor strikebreaking tactics and an incident involving the James Gang, where a dynamite attack on a cabin killed an innocent child.

Evolution of Municipal Police and Forensic Record-Keeping

  • Municipal Detective Forces

    • New York City was the first American municipal department to formalize plainclothes investigations, establishing a unit of 20 detectives in 1857.

  • Identification Systems and Record Keeping

    • Rogues' Gallery: A centralized compilation of mugshots categorized by criminal trade, used to identify repeat offenders (ruffians, hooligans, or modern gangsters).
    • Mulberry Street Parade: A daily 9:00 AM transfer of arrested prisoners from the station house to the central jail via open wagons. This direct display evolved into the modern "Perp Walk."
      • Modern Case Example: In Montgomery County, PA, a 58-year-old 25-year veteran police officer was arrested by county detectives and charged with voluntary manslaughter after fatal shooting a drunk 22-year-old pounding on the wrong residential door following a party.
    • Criminal Investigation Bureau (CIB): Expanded identification databases from simple mugshots and fingerprints to detailed records of tattoos, surgical scars, and amputations.
    • Sworn vs. Non-Sworn Roles:
      • Sworn Detectives: Conduct field interviews, write search warrants, execute arrests, and carry firearms.
      • Non-Sworn Analysts: Office-based personnel who process cellular records, map historical tower data, plot movements, and analyze link networks.

Overview of Federal, State, and Municipal Law Enforcement Agencies

  • Federal Investigative Development

    • United States Secret Service: Created during the Civil War under the Department of the Treasury to combat counterfeit currency. Presidential protection duties were assigned informally and later mandated by Congress following the assassination of President William McKinley (the third assassinated president, following Abraham Lincoln and James A. Garfield, preceding John F. Kennedy).
      • Uniformed Division: Provides physical perimeter security, metal detector screening, and venue protection for presidential candidates.

  • State Law Enforcement Models

    • California Bureau of Criminal Identification and Investigation (1905): Established to centralize information across a state spanning over 200 miles in depth and running the equivalent length of the US East Coast (Boston/New York to Florida).
    • Pennsylvania State Police (1906): The prototype for modern paramilitary state police agencies. Created with centralized command to manage uniform patrol, crash investigations, and statewide criminal investigations.
      • Historical Perception: Early state police units were initially viewed as industrial strikebreakers (e.g., during conflicts involving the Molly Maguires in coal regions).
    • Regional Administrative Differences:
      • Northeast Quadrant (Virginia east of the Ohio River, plus AR and KY): Relies predominantly on full-service State Police departments.
      • Rest of the US: Operates primarily with a dual model consisting of a State Highway Patrol (traffic enforcement) paired with a state-level bureau of investigation (e.g., Georgia Bureau of Investigation [GBI], South Carolina Law Enforcement Division [SLED/SCAR], Florida Department of Law Enforcement [FDLE], and the Texas Rangers [a selective unit of 100–200 agents]).
    • Agency Scale Examples:
      • NYPD: ~35,000–36,000 sworn officers.
      • Chicago PD: ~18,000–20,000 sworn officers.
      • FBI: ~14,000 agents.
      • Los Angeles County Sheriff's Department: ~14,000 personnel.
      • Riverside County Sheriff's Department (CA): ~6,500 deputies.
      • Harris County Sheriff's Office (TX): ~6,000 personnel.

History of Federal Law Enforcement, Prohibition, and Constitutional Rights

  • Federal Bureau of Investigation (FBI)

    • Formed in 1908 as the Bureau of Investigation; formally designated the FBI in 1935.
    • J. Edgar Hoover took control in 1924, instilling strict professional requirements: mandatory college degrees, background investigations, physical fitness standards, and formal testing protocols.
    • Homeland Security Investigations (HSI): Established post-September 11, 2001; currently the largest federal law enforcement agency.

  • Prohibition, Federal Taxation, and Drug Enforcement

    • Volstead Act (1920): Enforced the 18th Amendment banning alcohol; repealed in 1933. Plagued by widespread corruption. Over 13 years, 60 Prohibition Bureau agents were murdered (compared to ~115 FBI agents killed in line-of-duty line actions over nearly 90 years).
    • Tax Foundations: Most federal enforcement historically derived from revenue collection under the Department of the Treasury (e.g., IRS, original ATF, original Bureau of Narcotics created in 1930, which later evolved into the DEA).
    • Modern Drug Trends: Fentanyl added to street drugs drives 95%–98% of contemporary fatal overdoses due to extreme potency.

  • The Due Process Revolution

    • Appointed by President Dwight D. Eisenhower, Supreme Court Chief Justice Earl Warren led the "Due Process Revolution" during the 1960s.
    • Targeted systemic police misconduct and failure to follow constitutional procedures.
    • Primary Legal Focus: Expanded Fourth Amendment rights regarding Search and Seizure and Sixth Amendment rights regarding Legal Representation (with interrogation protections developing concurrently).

Forensic Science Foundations, Locard's Exchange Principle, and Biometrics

  • Nature of Physical Evidence

    • Requires scientific evaluation across multiple disciplines (geology, physics, chemistry, biology, mathematics).
    • Disguised Weapons: Objects such as writing pens may conceal functioning firearms, hidden knives, or scalpel-like blades capable of severing major arteries.
    • Zip Guns: Historical improvised firearms made from metal tubes, 0.22 caliber rounds, and rubber-band-driven firing pins.

  • Edmond Locard

    • Known as the Father of Forensic Science.
    • Locard's Exchange Principle (Theory of Exchange): Whenever two objects come into contact, a cross-transfer of physical material occurs ("Everywhere you go, you leave some of yourself and you take some of what's there").
      • Transfer Examples: Microscopic pet hairs transferring from home furniture to clothing and onto black vehicle headliners; shedding skin flakes, hair roots, and trace saliva droplets generated during normal speech.
    • Poroscopy: The study of microscopic sweat pores in friction ridge skin; established the 12-point agreement model for fingerprint comparison.

  • Alphonse Bertillon

    • Known as the Father of Criminal Identification.
    • Developed Anthropometry: A system of precise physical body measurements designed to track individual identities; eventually replaced by dactylography (fingerprinting). Serves as the historical precursor to modern automated facial recognition.

  • Identification Systems Timeline

    • Dactylography: Fingerprint analysis; replaced anthropometry as the global identification standard.
    • DNA Analysis: Structure described in the 1950s (Crick et al.); DNA profiling/fingerprinting technology for suspect inclusion or exclusion developed in the mid-1980s.