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Note: Please be advised that this lesson contains discussions of sexual assault and sexual assault investigations.

Sexual Assault Cases

Post Sexual Assault Support

According to a 2017 overview of the "National Best Practices for Sexual Assault Kits: A Multidisciplinary Approach" from the National Institute of Justice:

"Behind every sexual assault case is a person whose life has been irrevocably altered. The first responders, law enforcement investigators, forensic nurse examiners, laboratory analysts, victim advocates, and attorneys who support and interact with victims in different ways, have the opportunity to work together to positively impact a victim's post assault experience and improve healing and recovery"

Sexual Assault Kit

Whenever a sexual assault is reported, the victim is asked to participate in the collection of a Sexual Assault Kit (SAK). This kit is a package of materials used to collect samples of evidence from the victim's and/or suspect's body. The contents of the kit vary by jurisdiction, but the kit generally includes swabs and collection envelopes for biological materials and underwear. This type of evidence is generally collected at the hospital by a medical professional such as a nurse trained in sexual assault examination.

An example of a Sexual Assault Kit. The kit is a box containing envelopes for evidence, swabs, and labels.
Courtesy of the U.S. Government Accountability Office (GAO).

Knowledge Check #1

What does SAK stand for?

Sexual Assault Kit Testing

Sexual assault victims may choose for their kit to remain unreported or anonymous. Kits that are submitted may await testing due to a backlog in cases or remain unsubmitted because of lack of communication or delays in transport between the testing site and forensics laboratory.

An eviddence collection kit with evidence containers.

Improving the Response to Sexual Assaults

In 2017, the National Institute of Justice published a report entitled "National Best Practices for Sexual Assault Kits: A Multidisciplinary Approach". This document seeks to improve the response to sexual assault by addressing short-comings in evidence collection, tracking, storage, submission, and analysis -- all of which lead to delays in justice and a decrease in future victim's likelihood of reporting their assault. The report recommends 35 areas for improvement, a few of which will be discussed here.

Engaging the Victim

Successful investigation of sexual assault cases requires cooperation from the victim. First, the victim must be willing to report the assault. Then, he or she must relive the scenario as they share their account of the events that occurred and finally agree to go to the hospital for the collection of the SAK. Sexual assault responders should use a victim-centered and trauma-informed approach when engaging with victims of sexual assault.

A sexual assault victim being interviewed.

Trauma Impact

According to 2017 "National Best Practices for Sexual Assault Kits: A Multidisciplinary Approach" full report from the National Institute of Justice:

"Experiencing major traumas, such as sexual assault, has a significant effect on victims' health and well-being. It is important that those responding to sexual assault victims understand the impacts of trauma and its effects on victims' behavior. The use of trauma-informed approaches places an emphasis on

  • "Attending to victims' emotional safety, as well as their physical safety;
  • "Strengthening victims' capacity to recover from the traumatic effects of abuse and violence by providing information, resources, services, and support; and
  • "Educating victims, service providers, and the general community about the impact of trauma on survivors' health and well-being."
A sad woman rubbing her forehead.

Rape Crisis Center

Studies have shown that how law enforcement treats victims can affect their engagement in the criminal justice system. Investigators should seek to be compassionate and sensitive and perform their tasks in a non-judgmental manner. Officers should provide, in writing, the contact information of the local Rape Crisis Center (RCC). In many areas, RCCs provide advocates that can help victims through the interview process, transport them to the hospital for SAKs collection, and provide support throughout the legal process.

Collecting Victim Information

When collecting information from a victim, officers should interview, not interrogate.

  • An interview is like a conversation, with open-ended questions that allow the victim to share as much as they feel comfortable.
    A police officer interivewing a woman.
  • In an interrogation, the investigator dominates most of the conversation and their tone is accusatory; specific information is often being sought, like a confession.
    A police officer interrogating a woman. The woman looks uncomfortable.

Obtaining Offender Information

If the offender is unknown, the officer should seek to obtain a detailed physical description of the person and his or her vehicle as well as a sequence of event, including:

  • the point of entry to the crime scene
  • what the offender may have brought to or taken from the crime scene
  • things the offender touched or moved
  • any threats made by the offender
  • any use of force or weapons

Victim Interview

The victim's ability to think clearly may be altered by the assault. Trauma victims often recall information over time. Interviews may be postponed if the officer senses the victim is in distress or not thinking clearly.

The victim's exact words should be recorded in the report and placed in quotations. From the information gathered, investigators should write a detailed narrative, being careful not to make any assumptions about what occurred or use words that imply consent.

A man interviewing a woman. The man is writing on a clipboard.

Knowledge Check #2

Determine whether these terms are descriptions of interviews or interrogations.

Terms:

  • Seeks to record this person's version of facts
  • Conversational
  • Investigator-dominated
  • Non-accusatory
  • Accusatory
  • Seeks a confession from a suspect

Answer:

Interview Interrogation
Non-accusatory Accusatory
Conversational Investigator-dominated
Seeks to record this person's version of facts Seeks a confession from a suspect

Sexual Assault Resources

Rape, Abuse & Incest National Network seeks to prevent incidences of sexual abuse, help victims, and ensure justice.

Read How to Help Someone You Care About: Tips from RAINN for how to support someone affected by sexual trauma.

DNA Evidence

DNA evidence can be a key factor is achieving justice during a sexual assault case. However, challenges with evidence collection, storage, tracking and processing have created a backlog of evidence that is an obstacle to prosecuting perpetrators. In some cases, evidence from the SAK was never sent to the crime lab. In other cases, they arrived at the crime lab but were never tested as the volume of cases coming in is greater than the capacity of the lab.

Several recommendations have been made to alleviate this backlog and reduce the time frame for processing future cases.

Chain of Custody

Law enforcement agencies and laboratories should partner to use one evidence tracking system. A typical chain of custody should be included which gives the data/time/identity of the individual who collected the evidence as well as any persons in possession of the evidence during transport, submission, and acceptance. Evidence should also contain a unique number and a scannable barcode.

An investigator cutting open a paper evidence bag. The bag is labeled and taped closed.

Knowledge Check #3

Which of the following people should be included on the chain of custody?

  1. The officer who collects the evidence and packages it at the scene.
  2. The officer who transports the evidence to the laboratory.
  3. The laboratory worker who receives the evidence and sorts it according to the appropriate department.
  4. The forensic scientists who analyzes the evidence.
  5. The officer, lab worker, and forensic scientists should all be included on the chain of custody.

Answer: e. The officer, lab worker, and forensic scientists should all be included on the chain of custody.

Collecting Sexual Assault Kits

The National Institute of Justice (NIJ) recommends that law enforcement collects SAKs from the hospital or clinic no more than three business days after the collection of the kit and submits the kit to the laboratory within seven days. After analysis, kits should be given back to law enforcement or placed in storage at the laboratory. The storage location should be recorded within the evidence tracking system shared by the law enforcement agency and laboratory.

Knowledge Check #4

How soon after retrieving a SAKs from the hospital should law enforcement transport it to the laboratory for analysis?

  1. Within 3 hours
  2. Within 3 days
  3. Within 7 hours
  4. Within 7 days

Answer: d. Within 7 days

Laboratory Analysis Goal

The goal of laboratory analysis of SAKs kits should be to establish a CODIS-eligible DNA profile. As discussed in previous lessons, sample analysis often begins with serology tests to determine the type of bodily fluids present. Instead, to process SAKs quickly, a “Direct to DNA” approach is recommended. A portion of each swab is retained so that serology testing can be performed later if needed.

CODIS-eligible DNA Profile

The diagram below shows the factors that must be considered in developing a CODIS-eligible DNA profile.

A flowchart demonstrating if a DNA profile is CODIS/NDIS eligible. The chart starts with asking 'Has a crime been comitted?' If no, the profile is not eligible for NDIS. If yes, it is then determined if there were consensual partners. If not, the profile is eligible for CODIS/NDIS. If yes, then it is determined if elimination samples have been requested or obtained. If no, then the profile is not eligible for CODIS/NDIS until the elimination sample is requested. If yes, then it is eligible for CODIS/NDIS.
Courtesy of the National Institute of Justice

Elimination Samples

Elimination samples are needed if a victim has had consensual sexual relations five days prior to or following the occurrence of the assault. This consensual partner's DNA will need to be eliminated prior to CODIS entry.

A lab technician pipetting a liquid DNA sample into a test tube.

Considering Other Types of Evidence

While DNA can provide valuable evidence, it is not the only type of evidence in sexual assault cases, and often not the most important.

While testing SAKs for DNA is important, the testing of these kits does not always provide CODIS-eligible DNA evidence. Research in 2011 and 2012 revealed less than half of the submitted SAKs resulted in CODIS entries. This may be due to degradation of the sperm prior to or after collection or the lack of sperm evidence due to condom use and other precautions by the perpetrator.

Other Types of Evidence Examples

In other cases, DNA evidence may not be that valuable. For example, the suspect may admit to having sex with the victim but claim it was consensual. In this case of “he said, she said,” the presence of the male sperm is not probative providing proof or evidence .

Investigators should not rely solely on DNA but use their skills to identify, collect, process, and analyze other types of evidence including trace evidence, cellphone and digital information, impressions, prints, and toxicology testing and identification of drugs or other chemicals in the human body .

Sexual Assault Scenario

Scenario: "After an evening of hanging out with friends, a 20-year-old woman decided to get a ride home with her ex-boyfriend. They had broken up several months before but had remained friendly with each other. During the drive, the young man started talking about how they should get back together because he missed the relationship they once had. However, she was not interested and wanted to remain friends.

"Only blocks from her home, the man stopped the car and suddenly turned violent. Grabbing her neck, he began to force himself on her. As he ripped off her clothes, she managed to grab a small pocketknife from her purse, but he took the knife from her and broke it. He then dragged her by the legs out of the car and raped her in a nearby wooded area. Afterwards, he stole her credit cards and drove away. The woman managed to walk to her home and called the police to report the rape. She was brought to the hospital, where she was interviewed, photographed, and examined for several hours. Evidence was collected for a sexual assault kit (SAK)."

"When the police spoke with the young man, he described a very different series of events. He claimed that he and his ex-girlfriend had a fun evening at the party and that she came on to him and wanted to get back together. He admitted to taking some drugs that evening and thought he blacked out briefly. When he woke up, he claimed that his ex-girlfriend was on top of him and they had consensual sex. He said their clothes were everywhere, and he must have accidentally taken her credit cards when he gathered his things. He denied ever handling a knife."

Knowledge Check #5

True or False: DNA results from the SAK would be probative in this case.

  1. True
  2. False

Answer: b. False

Knowledge Check #6

True or False: Fingerprints from the knife would be probative in this case.

  1. True
  2. False

Answer: a. True

Credits

United States, Department of Justice, Office of Justice Programs, National Institute of Justice. "National Best Practices for Sexual Assault Kits: A Multidisciplinary Approach," 7 Aug. 2017, https://nij.ojp.gov/topics/articles/national-best-practices-sexual-assault-kits-multidisciplinary-approach.

United States, Department of Justice, Office of Justice Programs, National Institute of Justice. National Best Practices for Sexual Assault Kits: A Multidisciplinary Approach, 1 Aug. 2017, www.ncjrs.gov/pdffiles1/nij/250384.pdf.

Waltke, Heather, et al. “Sexual Assault Cases: Exploring the Importance of Non-DNA Forensic Evidence.” National Institute of Justice Journal, no. 279, 2018, nij.ojp.gov/topics/articles/sexual-assault-cases-exploring-importance-non-dna-forensic-evidence.