Key Takeaways
- South Bend Police are using a Vacuum Metal Deposition (VMD) chamber to extract DNA from items that previously yielded no usable genetic material.
- Only four VMD machines exist nationwide; South Bend is the second police department in Indiana to acquire one.
- The device vaporizes precious metals (gold or silver), which then adhere precisely to microscopic traces of touch DNA, even on aged, cleaned, or water‑submerged evidence.
- Investigators hope the technology will revitalize cold‑case murder investigations by revealing new DNA leads on weapons, clothing, and other items once considered exhausted.
- The VMD was purchased through a Justice Assistance Grant, marking it as the department’s largest grant award to date.
- Crime scene technicians and cold‑case investigators are currently undergoing training, establishing standard operating procedures, and integrating case‑specific information to maximize the device’s effectiveness.
Overview of the Vacuum Metal Deposition Technology
A vacuum metal deposition chamber is a specialized piece of equipment that heats precious metals such as gold or silver until they vaporize inside a sealed, low‑pressure environment. The metal atoms then condense onto surfaces within the chamber, forming an ultra‑thin, uniform coating. When forensic evidence is placed inside, the deposited metal adheres wherever microscopic residues—such as sweat, skin cells, or other trace biological material—are present. This selective binding creates a visible contrast that highlights the exact locations of touch DNA, making it possible to collect genetic material from surfaces that would otherwise yield little or no detectable DNA.
Why South Bend Police Adopted the VMD
Detectives in South Bend noted that traditional DNA recovery methods often fail on items that have been wiped, laundered, exposed to water, or aged for many years. Despite having physical evidence like clothing or a murder weapon, investigators frequently obtained inconclusive or negative results, leaving promising leads unexplored. The VMD offers a way to “re‑examine” those items by revealing the precise spots where a perpetrator’s touch may have left behind cellular material, thereby increasing the chances of obtaining a usable DNA profile for comparison with offender databases or familial searches.
Rarity and Significance of the Device
Nationwide, only four VMD chambers are currently in operation, making the technology exceptionally rare in law‑enforcement settings. South Bend’s acquisition places it among a select group of agencies pioneering this forensic approach. Being the second police department in Indiana to employ the device underscores the department’s commitment to adopting cutting‑edge tools and highlights the potential for other jurisdictions to follow suit once proof‑of‑concept results are demonstrated.
How the VMD Enhances DNA Recovery on Challenging Evidence
According to Crime Scene Technician Zariah Walker, the vaporized metals cling to the exact locations where fingerprints or fine DNA were deposited, regardless of how much time has passed or how thoroughly an item has been cleaned. This capability extends to murder weapons that have been scrubbed of blood, objects that have been submerged in water for extended periods, and items that have undergone multiple environmental stresses. By preserving the spatial distribution of trace evidence, the VMD allows analysts to target swabs or lifts precisely where DNA is most likely to be present, improving both the quantity and quality of the recovered genetic material.
Impact on Cold‑Case Investigations
Cold‑Case Investigator Craig Whitfield expressed optimism that the VMD could breathe new life into homicide cases that have remained unsolved for decades. Many of these cases suffer from degraded or contaminated evidence that standard techniques cannot exploit. By applying the VMD to old clothing, weapons, or other items stored in evidence lockers, investigators hope to uncover previously undetectable DNA profiles that may match suspects in national databases or lead to familial matches, thereby generating fresh investigative leads where none existed before.
Training and Procedure Development
Before the VMD can be used routinely, the South Bend Police Department’s forensic team is completing an intensive training program. Technicians are learning how to operate the chamber safely, calibrate metal deposition rates, and prepare evidence for optimal results. Simultaneously, they are drafting standard operating procedures (SOPs) that outline evidence handling, chain‑of‑custody documentation, contamination controls, and post‑deposit analysis steps. This groundwork ensures that the technology is applied consistently and that results are admissible in court.
Collaboration with Detectives and Case Information
Walker emphasized that the forensic team works closely with detectives to contextualize each piece of evidence before VMD processing. By reviewing case facts, crime‑scene photographs, officer reports, and investigative notes, technicians can identify which items are most likely to yield valuable touch DNA. This collaborative approach maximizes the efficiency of the chamber’s use, avoids unnecessary processing of low‑value items, and focuses resources on evidence that has the highest potential to advance investigations.
Funding Through a Justice Assistance Grant
The VMD chamber was financed by a Justice Assistance Grant (JAG), which represents the largest grant award ever received by the South Bend Police Department. The grant underscores federal support for innovative crime‑solving technologies and reflects confidence in the department’s ability to implement and evaluate new forensic methods. Securing such funding not only covered the purchase price of the equipment but also allocated resources for training, maintenance, and ongoing procedural development.
Future Prospects and Broader Implications
As the team becomes proficient with the VMD, South Bend anticipates sharing its findings with other law‑enforcement agencies and forensic laboratories. Successful case outcomes could encourage broader adoption of vacuum metal deposition across the country, potentially transforming how touch DNA is recovered from challenging evidence. Moreover, the technology’s ability to retrieve genetic material from items previously deemed unsuitable may lead to the resolution of additional cold cases, bring closure to victims’ families, and enhance public safety by removing repeat offenders from the community.