Mercy Medical Center in Baltimore is using Forensic Light Sources to detect bruising not visible to the naked eye.

Mercy Medical Center in Baltimore is using Forensic Light Sources to detect bruising not visible to the naked eye.

Posted on: Jan 22, 2019

An act of Mercy in Baltimore

How a team of nurses revolutionized the investigation of strangulation cases in the area of domestic assault.

Mercy Medical Center in Baltimore City Maryland had a problem.

Hundreds of women were coming into its emergency room as strangulation victims. But despite witnesses and their own accounts, the victims often lacked any visible marks on their necks to prove in a court of law that strangulation had occurred.

The problem vexed Debra Holbrook. A registered nurse, she is the Forensic Nursing Director with Mercy Medical Center’s Forensic Nursing Examiner Program.

A forensic nurse provides specialized care for patients who are victims of trauma. Forensic nurses also have specific knowledge of the legal system and skills in injury identification, evaluation and documentation.  A forensic nurse often collects evidence, provides medical testimony in court, and consults with legal authorities.

Part of that evidence collection included the use of an Alternative Light Source (ALS), like the ones made by SPEX Forensics, a Division of HORIBA Scientific. These sources, at specific wavelengths, made certain materials fluoresce, so they could detect the presence of things like saliva, semen and lubricants.

Holbrook, who founded a Forensic Nurse Examiner Program in Delaware, learned something else. If you changed the wavelength of the alternative light source to a higher wavelength, contusions and injuries, unseen by the naked eye went through a process of absorption. The absorption of the light source revealed a visible impression that would uncover the injuries that were previously undetected.

What’s more, the effect could be photographed, so a court didn’t have to depend on the testimony of a forensic nurse alone.

“If we changed the wavelength to the lower 400 to 500 (nanometer) range, we found absorption with different colored goggles,” Holbrook said. “We could see absorption under the skin. I could see significant amounts of absorption in the 450 (nm) to 500 (nm) range using orange or red goggles. The injuries matched how they stated they were assaulted.”

Depending on its wavelength, light can penetrate the skin, and has the potential to detect bruises, which are primarily located below the level of the epidermis, according to the National Institutes of Health.

The amount of reflection and absorption picks up differences in color. Wavelengths of light that are reflected become the visible color of the skin’s surface, while absorbed light appears as a darker color.

Colored filters (e.g., colored goggles, colored camera lenses) used to block the reflected light allow the fluorescent light to be seen as brighter, while absorbed light appears dark in comparison.

Holbrook found 90 to 95 percent of the hospital’s strangulation victims showed the absorption. Her own published studies linked the absorption phenomena to an injury under the skin.

“The absorption that we are seeing in the 450-500nm range mirrors injuries we expected to see on some parts of the body,” she said. “Now it gives patients who are victims something to use in court other than their word.”

Holbrook and her associates testify in court. In many of the cases, Holbrook said, defendants plead guilty because the alternative light source evidence further supports the preponderance of evidence against the defendant.

“The use of ALS has changed the practice of forensic nursing in Baltimore,” she said. “It is a staple for our care and investigation.

Holbrook has taught at national conventions and conferences of forensic medical specialists and scientists. She has promoted the process across the county.

Mercy Medical Center uses SPEX Forensics Alternative Light Sources for its forensic investigations, including the Mini-CrimeScope 400, CrimeScope FOCUS and HandScope LED.

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