Sexual Crimes and Sexual Assault

Topic = Sexual Crimes and Sexual Assault - DNA Issues

Definition of Sexual Assault

  • Sexual Assault: Defined as a physical assault of a sexual nature directed toward another person, which occurs under the following conditions:

    • Individual does not give consent.

    • Consent is given as a result of intimidation or fraud.

    • Individual is legally deemed incapable of giving consent due to youth or incapacity.

Variation in Definitions Across Australia

  • Key Elements of Sexual Assault:

    • Sexual activity occurred without consent.

    • The defendant was aware that there was no consent.

    • The defendant’s actions were voluntary.

    • Elements 1 and 2 occurred simultaneously.

Changes in Sexual Assault Law

  • Historically, rape and sexual assault were defined as property offenses.

    • Early legal perspective: Women failing to give consent would demonstrate active resistance.

    • Current legal perspective: Active willingness to participate in sexual activity must be clearly shown; mere submission does not constitute consent.

Sexual Assault Statistics

  • Reported Incidents: 36,318 sexual assaults reported, equivalent to a rate of 136 per 100,000 individuals.

    • Notable trend: A steady increase across most jurisdictions; for instance, Western Australia saw a 9% increase between 2022 and 2023.

Yearly Reporting Rates (2016-2023)

  • 2016: 95.3

  • 2017: 105.0

  • 2018: 105.4

  • 2019: 105.9

  • 2020: 107.2

  • 2021: 120.8

  • 2022: 126.1

  • 2023: 136.3

Location of Sexual Assaults

  • Majority occur in the home: 68% of assaults take place in private dwellings.

  • Breakdown of other locations:

    • Retail: 5%

    • Recreational: 4%

    • Other Community Locations: 11%

    • Street/Foopath: 5%

    • Transport: 4%

    • Outbuilding/Residential Land: 1%

Victim Demographics

  • Gender Statistics:

    • Female victims: 84%.

    • Boys aged 0-9 and 10-14 show similar totals.

    • Girls aged 15-19 represent the highest rates of sexual assault victimization.

Assailant Relationships to Victims

  • In over 85% of sexual assaults, the attacker is known to the victim.

    • More than half of these cases involve non-family members.

Global Context of Sexual Assault

  • The United States has the highest total number of individuals raped annually.

  • South Africa reports the highest rape rate, at 95.9 per 100,000 population.

    • Note: Only reported rapes are included, indicating potential inaccuracies in data.

Rape Myths

  • Common Myths:

    • Rape is a crime of passion.

    • Nice women do not get raped.

    • Women secretly want to be raped.

    • Most rapists are strangers.

    • Most sexual assault reports are false.

    • Men need not worry about being raped.

    • Rape cannot happen to me.

Additional Myths

  • Only young and attractive individuals are raped.

  • Only provocative individuals are raped.

  • Most rapes are interracial and not a serious issue, merely seen as sex.

  • Most non-acquaintance rapes are planned and rapists are usually sexual deviants.

Misconceptions about Causes of Rape

  • Things that do not cause rape:

    • Tight shirts, smiles, eye contact.

  • Things that may be misconstrued as causes:

    • Failure to say “NO,” clothing, unconsciousness, alcohol intake.

Impact of Sexual Assault

  • Common Reactions:

    • Increased feelings of unsafety.

    • Loss of control over personal life.

    • Decreased self-worth, feelings of being damaged.

    • Feelings of isolation and loneliness.

    • Distrust towards others.

    • Guilt about potentially provoking the attack.

Stages of Adjustment

  • Stages Post-Assault:

    • Shock: “I’m numb.”

    • Denial: “This can’t have happened.”

    • Anger: “What did I do? Why me?”

    • Bargaining: “Pretend it didn’t happen.”

    • Depression: “I feel so dirty and worthless.”

    • Acceptance: “Life can go on.”

    • Assimilation: “It’s part of my life.”

Investigation Challenges

  • Delayed reporting to law enforcement: Often days or weeks post-assault, which limits evidence collection and reliance on testimony.

  • Low reporting rates for various reasons:

    • Embarrassment and feelings of guilt/remorse.

    • Fear of being labeled as a rape victim.

    • Intimidation from the perpetrator or their associates.

Reporting Rates of Various Crimes to Police

  • Statistics:

    • Varied reporting rates for different crime categories, suggesting sexual assault has some of the lowest reporting rates.

Sexual Assault Conviction Rates

  • Conviction Statistics from NSW (2013):

    • Total reports: 4500.

    • Reports charged: 3951.

    • Reports resulting in guilty verdict: 715.

    • Sentences involving jail time: 374.

    • Less than 5% of reported sexual assaults lead to actual imprisonment.

Sexual Assault Evidence Collection Protocol

  • Involves careful collection of victim's clothing immediately post-assault.

  • External examination of the victim's body and collection of trace evidence.

  • Written and photographic records of injuries must be maintained.

  • Fluid draws, testing for STDs, and collection of vaginal and anal swabs for perpetrator's body fluids are crucial.

Examination Protocol for Victim

  • Examination conducted in sections, with the victim draped to preserve dignity.

  • Photos are taken of only the relevant body parts, maintaining coverage of the rest.

Examination Protocol for Suspect

  • Law enforcement present during suspect examinations for procedural integrity.

  • Collection includes hair samples, body fluids, nail scrapings, and photographic records to document injuries or lack thereof.

Investigation Procedures

  • Steps Involved:

    • Witness interviews, evidence examination in crime labs, background checks, physician interviews, suspect interviews, record reviews.

  • Overburdened crime labs slow down the process, leading to longer times for analyses and results.

Factors Affecting Laboratory Processing Speed

  • Overburdened labs due to high case volumes.

  • Some scientific tests require multiple days for processing.

  • Cases prioritized based on imminent court dates.

Forensic DNA Issues

  • DNA Challenges in Evidence Collection:

    • Quantity of DNA often limited, necessitating conservation for potential re-analysis.

Enhancements in DNA Testing

  • Modern labs utilize rapid testing methods.

  • DNA can uniquely identify individuals as well as contributors from mixed stains, such as using STRmix™ technology.

DNA Degradation Factors

  • Environmental exposure, time, and improper storage conditions can degrade DNA, complicating testing and result interpretation.

Specific Issues with DNA Samples

  • Contamination risks during collection and processing.

  • Procedures must ensure segregation of evidence and suspect samples.

  • Mixed samples require specific analysis protocols to assess contributor profiles.

Differential DNA Extraction

  • A technique used to isolate male and female DNA from sexual assault evidence (typical in cases showing a mixture of DNA).

  • Involves:

    • Specimen treatment with SDS, EDTA, and proteinase K to lyse epithelial cells while preserving sperm.

    • Sequential centrifugation processes separate male sperm from female DNA.

    • Subsequent addition of DTT for sperm lysis and purification of DNA.

STRmix™ Forensic Software

  • Designed for resolving complex DNA mixtures, combining biological modeling and mathematical principles to recreate likely profiles from mixed DNA samples.

  • Used in casework since 2012, with implementations across the US, Canada, and the UK.

PCR Inhibitors in DNA Testing

  • Inhibitors may remain in DNA extractions, interfering with Taq polymerase activity.

  • Common inhibitors include:

    • Haemoglobin, blue dye from denim, fats, urine, and plasticware.

Strategies to Overcome PCR Inhibition

  1. Dilute samples.

  2. Increase Taq polymerase content.

  3. Introduce specific additives (e.g., Bovine Serum Albumin or Dimethyl Sulfoxide).

  4. Neutralize inhibitors using NaOH.

Identification of Sexual Predators

  • In forensic genetics, sexual predators classified based on DNA quality left at crime scenes:

    • Type I: Large amounts of DNA available for testing.

    • Type II: Limited or mixed DNA.

Famous Case: Bill Clinton and Monica Lewinsky

  • Investigated using DNA extracted from semen stains on an item of clothing (referred to as specimen Q3243-1).

  • DNA analysis involved digesting samples with HaeIII, identifying VNTRs, with a match probability of 1 in 7.8 trillion.

Small/Mixed DNA Analysis Characteristics

  • Use of sex-specific markers like Amelogenin and Y-chromosome markers for differentiation in cases involving male and female DNA contributions.

  • Amelogenin: Present on both X and Y chromosomes, with distinct PCR product lengths between genders.

  • Y-chromosome STRs are useful for distinguishing male DNA in mixtures during rape investigations.

Review Questions

  • Identify myths associated with rape and sexual assault.

  • Describe the sexual assault evidence collection procedures for victims and suspects.

  • Outline forensic DNA issues related to sexual assaults.

  • Explain the Differential DNA Extraction process utilized in sexual assault cases.

  • Define PCR inhibitors and strategies to overcome them.

  • Discuss the VNTR testing used to link Bill Clinton to Monica Lewinsky.

  • Explain the significance of Amelogenin and Y chromosome STR markers in sexual assault investigations.