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No Rape Case Goes Unanalyzed: A Rapid Approach to Sexual Assault Evidence

By Eva Steinberger, PhD, Assistant Bureau Chief; Julie Renfroe, MBA, Criminalist Supervisor; Meg Aceves, MS, Criminalist Supervisor; and Gary Sims, MPH, Casework Laboratory Director, California Department of Justice, Bureau of Forensic Services, Richmond, California

n many cases of sexual assault, crime laboratories have generally lacked the resources needed to use forensic DNA within the short response time that is most beneficial to a criminal investigation. This lack creates problems in the system by slowing investigations and preventing justice for many victims. A solution to this emerged when forensic scientists at the California Department of Justice (DOJ) Jan Bashinski DNA Laboratory in Richmond developed a DNA processing method that is fundamentally different from the traditional approach. This rapid approach method, which combines innovative evidence triaging with a redesign of the evidence submission route, provides a sustainable process for a high-throughput program with a 15-day turnaround time.

As part of a pilot program, four California counties adopted Rapid DNA Service (RADS). Forensic hospital staff, law enforcement, and the laboratory staff spent 22 months using the method to analyze DNA in all cases where sexual assault evidence (SAE) was collected in a hospital. The methodology of RADS and the results from the four California counties’ initial adoption of the method follow.

Evidence Triage and Submission to the Laboratory

In the traditional approach to sexual assault cases, evidence is collected by forensic hospital personnel into a rape kit, which is stored by a law enforcement agency. Once a case is assigned, an investigator decides whether the evidence warrants a DNA analysis, then the kit may be submitted to a crime laboratory. Under RADS, two significant departures occur.

First, RADS uses evidence triage to identify the best evidence—the evidence most likely to yield the DNA profile of the perpetrator. As many as three evidence swabs, each taken from areas of the victim’s body most likely to yield probative results, are submitted for analysis. Which swabs are chosen is based on the professional judgment of the forensic hospital staff after evaluation of the victim and the incident history. The RADS swabs are in addition to the items included in the traditional rape kit collected according to established state procedures.1

Second, RADS swabs are packaged in a RADS envelope. (See figure 1.) This envelope is sent directly to the crime laboratory via overnight courier for processing and typing within 15 workdays from the start of batch analysis. The rape kit and any additional evidence are stored at the law enforcement agency until the results of the RADS process are known. (See figure 2.)
Figure 1: Contents of the RADS Envelope

Evidence Processing and DNA Analysis at the Laboratory

Most sexual assault evidence involves the separation of sperm cell DNA from all other cellular DNA. The traditional method for extracting sperm cell DNA is one of the most time-consuming, limiting factors in a high-throughput laboratory approach. In response to this major challenge, the DOJ Jan Bashinski DNA Laboratory dedicated time and personnel toward streamlining the analysis of sexual assault evidence. The result is a novel and very efficient process that is almost completely automated and does not rely on time-consuming microscopic examination.2 Using the RADS process, one individual can analyze as many as 20 cases simultaneously; complete the report; and, if appropriate, profiles can be uploaded into the FBI’s Combined DNA Index System (CODIS) within 15 days.

Interagency Collaboration

Under RADS, law enforcement no longer needs to preselect or prioritize cases for DNA analysis because the laboratory processes every case within the specified time frame. At the hospital level, the process must be aggressively triaged at the point of collection since the laboratory analyzes only three items. To make this approach work, all parties must be in agreement and possess a thorough understanding of the procedure and the roles of each in the process. For example, the agreement requires law enforcement staff to hold on to the traditional rape kit and any additional evidence until the RADS results are known. To provide maximum benefit, RADS was designed to yield results that can stand up in court without the requirement for the analysis of additional evidence. However, the crime laboratory staff must be flexible in the event that processing additional evidence is needed.

Furthermore, continuous process improvement based on the professional experience of all parties is essential for long-term success. Unless there is frequent communication among all stakeholders, the RADS approach will not work optimally and can possibly cause duplication of effort and unnecessary delays. For example, data collected so far show that body swabs (for example, from the victim’s breasts and neck) often yield a male DNA profile and may be the best evidence more often than originally thought. (See figure 3.) This finding has been communicated to all the stakeholders and serves to improve the overall process, most significantly during triage efforts.

The Effectiveness of the RADS Approach

Among the counties participating in RADS, requests for analysis of DNA evidence in rape cases have more than tripled. (See table 1.) However, evidence triaging combined with automated methodology reduces the processing time and allows the crime laboratory to analyze samples from every case collected at a hospital.

Table 1: Comparison of Cases Submitted per Year in RADS Counties
 Number of Cases
Total cases submitted from RADS counties in 2010 (pre-RADS)41
Average yearly number of RADS cases submitted161

RADS helps to alleviate one of the biggest concerns among sexual assault victims and human rights groups: that evidence either takes too long to be analyzed or is not analyzed at all. With RADS, victims are assured that their cases are active, evidence is being examined expeditiously, and law enforcement is doing all it can to resolve their cases in a timely manner. In cases where DNA results are obtained, victims and investigators are assured that the DNA database will be searched, increasing the likelihood that the perpetrators will be identified and brought to justice quickly.

As with any approach, there are tradeoffs to using RADS. So far, only 31 percent of the RADS cases processed resulted in a DNA profile from the evidence. This indicates that, in order to find every DNA positive case, many RADS cases with negative results will be processed. However, of the 31 percent of cases with DNA profiles uploaded to CODIS, 51 percent have yielded a CODIS hit. In addition, law enforcement agencies have requested the analysis of additional evidence in only 9 percent of cases. (See table 2.) That is, the triaged evidence submitted apart from the SAE kit was sufficient for law enforcement investigators.

Table 2: RADS Metrics
 Number of Cases
Total cases submitted, May 2011 – February 2013295 
Cases with searchable DNA profiles developed91(31%)* 
Cases with CODIS hits46(51%)**
Cases with additional evidence submitted28(9%)* 
* Percentage calculated against the total number of cases submitted.

** Percentage calculated against the total number of cases with searchable DNA profiles.

Although the number of analyzed sexual assault cases has increased, the triaged evidence is processed very quickly using the RADS approach. Traditionally, a law enforcement agency would wait until every item of evidence in the SAE kit was analyzed before receiving a report—a model that has led to analysis backlogs. Since the RADS reports are received by the law enforcement agency within a short turnaround time, analysts’ time is freed up making the analysts available to work on the few cases where additional evidence analysis is needed. Overall this process leads to the elimination of SAE kit backlogs because data have shown that the majority of RADS cases do not require further evidence examinations.

The RADS program has proven effective at the law enforcement, hospital, and laboratory level; however, the effectiveness of the RADS approach at the prosecutorial level can be measured only through the prosecuting agencies’ successful adjudication rate. At present, it will take several years until enough cases have gone through the court system to allow a reliable evaluation of the effectiveness of RADS evidence in the criminal justice system.


RADS is still a pilot project; although, based on the level of success seen in the first 22 months, it is likely to be adopted permanently by the participating counties. Requests by additional agencies to participate in the RADS program indicate a trend toward acceptance of evidence triaging for DNA analysis in sexual assault cases. The initial conclusions from the pilot indicate that RADS

  • allows for the processing of triaged evidence from all sexual assaults within 15 days from the start of batch analysis; and
  • combines automation with reduced processing time, allowing for a threefold increase in casework capacity.

The initial conclusions from the pilot also strongly indicate that body swabs may yield the best evidence. Although they account for one-fifth of the swabs submitted, they account for almost half of the searchable CODIS profiles. (See figure 3.)

Victims of sexual assault deserve justice. The benefits of RADS, which include the assurance that no rape kit will go untested, far outweigh any drawbacks. And, with broader adoption and further streamlining, RADS could significantly reduce the number of unanalyzed cases. The benefit for victims is undeniable, and this benefit by itself is a major reason for law enforcement, crime laboratories, and forensic hospital staff to employ this team approach. ♦


1California Penal Code 13823.11 (2011), the minimum standards for the examination and treatment of victims of sexual assault or attempted sexual assault, including child molestation and the collection and preservation of evidence therefrom.
2William R. Hudlow and Martin R. Buoncristiani, “Development of a Rapid, 96-Well Alkaline Based Differential DNA Extraction Method for Sexual Assault Evidence,” Forensic Science International: Genetics 6, no. 1 (2012): 1-16; William R. Hudlow and Martin R. Buoncristiani, “Material Modifications for the Alkaline Differential Extraction Method for Sexual Assault Evidence,” Forensic Science International: Genetics 7, no. 4 (2013): e104–105.

Please cite as:

Eva Steinberger et al., "No Rape Case Goes Unanalyzed: A Rapid Approach to Sexual Assault Evidence," The Police Chief 80 (September 2013): 52–54.



From The Police Chief, vol. LXXX, no. 9, September 2013. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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