Featured Research

from universities, journals, and other organizations

New Method For Processing Rape Evidence Could Eliminate Crime-lab Backlogs

Date:
May 7, 2008
Source:
University of Virginia
Summary:
Approximately 250,000 items of sexual assault evidence are mired in three- to 12-month backlogs awaiting analysis in US forensic laboratories. A forensic chemist has now developed a method for handling rape evidence that reduces part of the DNA analysis time from 24 hours to as little as 30 to 45 minutes and improves the sperm cell recovery rate by 100 percent.

With approximately 250,000 items of sexual assault evidence mired in three- to 12-month backlogs as they await analysis in U.S. forensic laboratories, there is an alarming nationwide need for a time-efficient way to get this work done, according to a University of Virginia forensic researcher.

Jessica Voorhees Norris, a Ph.D. candidate in forensic chemistry at U.Va., has found a better way. She has developed a method for handling rape kit evidence that reduces part of the DNA analysis time from 24 hours to as little as 30 to 45 minutes and improves the sperm cell recovery rate by 100 percent. If her method was to be adopted by forensic labs – and the results accepted by courts – the backlog could potentially be reduced within months.

"There is an overwhelming demand for DNA analysis of sexual assault evidence, but laboratories have neither the funding nor the manpower to handle the caseload in a timely manner," Norris said. "Juries have come to expect DNA evidence in sexual assault cases, but forensic labs are not able to perform in a timely and efficient manner due to limitations in the currently used technologies."

Norris has spent much of her career working in laboratories and long ago realized that new methodologies would be needed to keep up with the growing accumulation of unanalyzed samples. She has devoted her doctoral research to developing more effective and time-efficient methods.

When a woman is sexually assaulted and comes forward to the police, a sample is taken from the vagina with a cotton swab, which is then sent to a forensic lab. In high-profile cases, the analysis is usually performed immediately, though overnight incubation is required to achieve a result.

In most routine cases, though, the sample is put into storage, sometimes for as long as a year, before it finally reaches its turn in the cycle to be analyzed or when the case approaches a court date. The sample may degrade during the waiting period, resulting in a compromised finding.

Lab technicians must perform a number of steps to get their results. First, female and male cells must be removed from the swab with a special detergent. DNA from the vast number of epithelial cells from the victim's vagina must be separated from the far fewer sperm cells from the perpetrator. To do this, cells must sit overnight in an enzyme that bursts open the relatively fragile female cells to release their DNA for analysis. After the female DNA is removed, the highly durable sperm cells are burst open using stronger reagents. Once the DNA is extracted, profiles, in effect, are generated for both the victim and the attacker. It is a time-consuming process, one that has been in use for more than two decades.

Later, if a possible perpetrator is arrested, a sample taken from his mouth is analyzed to determine if there is a match with the sperm DNA that was removed from the victim.

Norris' method streamlines the method for separating the male and female DNA fractions, eliminating the need for the overnight incubation while doubling the recovery of sperm cells.

"This new process works extraordinarily well and could be implemented in forensic labs today," Norris said. "Unfortunately, getting labs to adopt a new protocol and getting legal systems to accept a new technology may take several years. In the meantime, the backlog of unanalyzed samples will continue to grow."

Norris noted that forensic science is not simply about proving guilt.

"Forensic science is about finding the truth in a timely manner," she said. "It is about using science to identify the guilty and exonerate the innocent."

Norris presented her findings at a recent meeting of the American Academy of Forensic Science. She will receive her Ph.D. in May this year and hopes to work as a scientist in a state- or federally funded forensics lab. She conducted her research in the lab of U.Va. chemistry professor James Landers.


Story Source:

The above story is based on materials provided by University of Virginia. Note: Materials may be edited for content and length.


Cite This Page:

University of Virginia. "New Method For Processing Rape Evidence Could Eliminate Crime-lab Backlogs." ScienceDaily. ScienceDaily, 7 May 2008. <www.sciencedaily.com/releases/2008/05/080507084218.htm>.
University of Virginia. (2008, May 7). New Method For Processing Rape Evidence Could Eliminate Crime-lab Backlogs. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2008/05/080507084218.htm
University of Virginia. "New Method For Processing Rape Evidence Could Eliminate Crime-lab Backlogs." ScienceDaily. www.sciencedaily.com/releases/2008/05/080507084218.htm (accessed July 31, 2014).

Share This




More Matter & Energy News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins