The use of an alternate light source (ALS), specifically ultraviolet (UV) light with a wavelength under 490nm, should be considered as a tool during searches for human remains [1].

Recent applications during HRD searches in Virginia by Search and Rescue Tracking Institute (SARTI) members have found the use of ALS with wavelengths in the 385-395nm range to be very effective. [2] Most members prefer the uvBeast V3 385-395nm handheld light.

A collaborative study between the Search and Rescue Tracking Institute (SARTI) and Virginia Commonwealth University [3] evaluated the effectiveness of alternate light sources (ALS) for locating skeletal remains through 36 mock searches. The study found that nighttime ALS searches more than tripled recovery rates compared with daylight searches and were completed in less time. Among the devices tested, the violet Crime-lite® (395–425 nm) produced the highest recovery rate, successfully locating 95% of the remains. These findings demonstrate the potential value of ALS as a search tool for locating skeletal remains that may be difficult to detect visually during daylight conditions.

Collagen, an organic protein found in bone, is responsible for the fluorescent properties of animal bones. According to Tzaphlidou [4], collagen represents more than 90% of the organic matrix in bone. This fluorescent property degrades over time, but may be visible for approximately 200+ years. Forensic cases less than 50 years should benefit from the use of UV light to observe bone's fluorescent properties.

Factors that could affect a bone's fluorescent properties include heat, pH, ultraviolet radiation, and moisture. 

According to a study by Gallant [5], remains that have been exposed to fire could not be differentiated from their surroundings using UV light.  A study by Lucia, et al. [6] found that thermal damage significantly affects the visibility and recovery of skeletal remains using alternate light sources (ALS). As thermal damage increases, visible fluorescence decreases, with less-damaged bones more readily detected during nighttime ALS searches, while charred and calcined bones are more effectively recovered during daylight searches. No significant differences were observed among the uvBeast, Crime Lite violet, or Crime Lite blue devices, although the low-cost and widely available uvBeast 385–395 nm remains commonly used by Virginia SAR personnel. When thermally damaged remains are suspected, a daylight search should be conducted first to recover fragile charred and calcined bone, followed by a nighttime ALS search to locate additional unburned or uncharred remains.

Search and Rescue Tracking Institute (SARTI) began utilizing UV light technology to search for human remains on October 26, 2023 in Virginia. [2] Searchers utilized 365nm, 385-395nm, and 390nm wavelength UV handheld ALS. This search produced successful results as searchers discovered 10 additional human bones. Since that time, SARTI has continued to deploy UV ALS with successful results on 11 searches across the Commonwealth of Virginia and continues to advance the science of ultraviolet light for the detection of human remains.

There are five distinct steps to describing how FLUORESCENCE works:

Experimentation Results Using UV Light vs. White Light at Night

Russell and Pyaett, Search and Rescue Tracking Institute, conducted a proof of concept experiment on November 10-11, 2023 to determine the effectiveness of searchers utilizing ultraviolet ALS to detect surface scattered skeletal remains. 

Results:

Searching at night with white light 15% detection rate

Searching during the day 30% detection rate

Search at night with UV light 73% detection rate

Photographic Examples

Additional examples of animal bones when exposed to ultraviolet light

Effects of Distance

Human Teeth

Note that the roots fluoresce more than the enamel

Note: Unless otherwise noted, the UV light photos above were utilizing a Gearlight UV black light flashlight S100 with an ultraviolet wavelength of 390nm. #ad

Search and Rescue Tracking Institute & Virginia Commonwealth University Research Collaboration

Standard Operating Procedures for Searching for Surface Scattered Skeletal Remains [7]:

• Identify and define the search area

  • Typically , a small, concentrated area of 1 acre

  • Can vary due to scavenging

• Scout search area during the day

• Deploy HRD K9 during the day

  • Mark any areas of interest

• Wait until dark to deploy ALS resources

  • At least 30 minutes after sunset

  • The darker, the better

• Ensure ALS team is trained and has proper PPE

  • Especially UV-rated eye protection

• Team is typically 6-10 searchers

  • With two behind to serve as navigator and scribe

• Conduct quick (5-minute) calibration exercise in local conditions with known bone sample (preferably non-human)

• Various forms of ALS are available

  • VDEM teams currently use uvBeast V3 385-395 nm

  • Batteries last about an hour - have spare charged batteries available

• Searching for small bones: tight grid, 1-5 meters depending on ground cover

  • Spacing of 3m = 98% POD; Spacing of 1m = 99.999% POD

• Bones only detectable if directly visible to eye

  • Difficult to detect under leaves or soil

  • Consider leaf blowers

    • Blow leaves onto tarps, then search area again using ALS

    • Move tarp with leaves to a non-search area

    • Remove leaves and check for small bones potentially blown onto tarp

References:

1. Swaraldahab, Mohamed A.H. , Christensen, Angie M. The Effect of Time on Bone Flourescence Implications for Using Alternate Light Sources to Search for Skeletal Remains. J Forensic Sci, Marck 2016, Vol. 61, No. 2.

2. Speiden, R., Pyeatt, R., Russell, J., Simmons, T. (2026). Detecting human remains with an alternate light source: Case studies. Journal of Forensic Identification.

3. Thompson, O. L., Simmons, T., Russell, J. A., Stockman, S., & Swall, J. (2024). Assessing the effectiveness of alternative light sources in search for skeletal remains (Master’s thesis, Virginia Commonwealth University). Department of Forensic Science, Virginia Commonwealth University.

4. Tzaphlidou M. Bone architecture: collagen structure and calcium/phosphorus maps. J Biol Phys. 2008 Apr;34(1-2):39-49. doi: 10.1007/s10867-008-9115-y. Epub 2008 Oct 15. PMID: 19669491; PMCID: PMC2577747.

5. Gallant A. Alternate light sources in the detection of bone after an accelerated fire: a pilot study. J Forensic Sci 2013;58(S1):S221-6.

6. Lucia, J., Simmons, T., Russell, J. A., Stockman, S., & Swall, J. (n.d.). Evaluation of the use of alternate light sources in the search for burned skeletal remains (Master’s thesis, Virginia Commonwealth University). Department of Forensic Science, Virginia Commonwealth University.

7. Koester, R. (2026). Lost Person Behavior: Abductions. Charlottesville, VA. dbS Productions LLC.

Interesting Articles:

Could a Tree Help Find a Decaying Corpse Nearby?

Reflection of ultraviolet radiation from different skin types

Luminescence of thermally altered human skeletal remains

Light: It's secrets revealed

Original Ultraviolet Light posting: September 17, 2023 Updated: September 9, 2026

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