How Advanced Sensors Aid in Trace Evidence Collection at Crime Scenes

By Soham NandiReviewed by Bethan DaviesFeb 27 2025

Forensic science has traditionally relied on various types of evidence to reconstruct crime scenes, with DNA analysis taking center stage.​​​​​​ But what happens when DNA isn’t available? That’s where trace evidence steps in—fibers, gunshot residue, chemical traces—all the tiny clues that can make or break a case.¹

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The idea behind trace evidence is simple: when two things come into contact, they exchange small amounts of material. This simple principle is the foundation of trace evidence analysis. And thanks to advancements in sensor technology, forensic investigators can now detect and analyze these microscopic traces with more precision than ever. Crime light imaging (CLI) sensors allow for high-resolution visualization of latent traces, while portable laser-induced breakdown spectroscopy (LIBS) sensors make it possible to conduct both on-site and lab-based forensic analysis.^1-3

As forensic technology continues to evolve, crime scene investigators must keep up, using specialized techniques to preserve and analyze trace evidence effectively.¹ Let’s take a closer look at the sensor technologies that are changing the game in forensic investigations.

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The Role of Sensor Technology in Forensic Investigations

Gone are the days of solely relying on traditional forensic methods. Recent advancements in sensor technology are giving crime scene investigators faster, more accurate, and non-destructive ways to collect and analyze trace evidence. But what are these sensors, and how do they work?

Types of Sensors Used in Trace Evidence Collection

1. Biosensors – Ever wondered how forensic teams can analyze sweat, blood, or fingerprints on-site? Biosensors detect biological markers and can even help infer details like a suspect’s age, gender, and lifestyle. Biosensors also facilitate on-site detection of ethanol and drugs in sweat, offering an alternative to breathalyzers.⁴

2. LIBS (Laser-Induced Breakdown Spectroscopy) – LIBS is an emerging forensic tool for in situ trace evidence analysis. It enables multi-elemental detection on surfaces, identifying materials like explosives, drugs, and gunshot residue (GSR). LIBS is particularly useful in analyzing fingerprints for chemical composition and determining the deposition order of forensic samples. It also aids in document forgery detection by distinguishing paper, ink, and toner compositions.³

3. Optical and Spectrophotometric Sensors – These sensors employ light-based techniques to detect latent fingerprints, determine bloodstain age, and analyze sweat composition. Spectrophotometric methods can identify differences in lipid content, aiding in forensic age estimation. Alternative light sources (ALS) can also help reveal hidden traces on various substrates by illuminating evidence at specific wavelengths.²

4. 3D Scanners and Photogrammetry – Crime scene reconstruction just got an upgrade. Modern 3D scanners can now be used to reconstruct crime scenes in detail, capturing spatial relationships between evidence items. Modern 3D scanners combine photography and laser distance measurements, enhancing scene documentation.²

5. Wearable and Microfluidic Sensors – Wearable biosensors, such as tattoo-based lactate sensors, allow for real-time sweat analysis. Microfluidic devices enable portable sample collection and analysis, making them valuable for field investigations.⁴

6. Gas Sensors – These advanced sensors detect volatile chemical compounds, producing unique 'fingerprint' patterns that are analyzed by artificial neural networks. This technology is vital in forensic applications, including drug identification, cadaver odor detection for determining time of death, and accelerant analysis in fire investigations. Thus, it offers faster and more reliable evidence collection.⁵

Where Are These Sensors Making the Biggest Impact in Crime Scene Investigations?

Forensic science has come a long way, and one of the biggest game-changers in crime scene investigations is the rise of portable sensors. These devices are making it faster and easier to analyze DNA, GSR, and gather critical evidence—right at the scene.

Take DNA analysis, for example. Traditionally, forensic teams had to send samples to a lab and wait days or even weeks for results. Now, microfluidic devices and portable PCR technology are cutting that time down dramatically. These tiny lab-on-a-chip systems streamline processes like DNA extraction and amplification, reducing contamination risks and making on-site testing a reality.⁶

One of the most exciting developments in this space is the SPEED device—a smartphone-operated portable digital PCR system. This handheld gadget syncs with a smartphone, allowing forensic teams to analyze DNA in real-time at the crime scene. It’s been tested across various DNA samples and has proven to be both reliable and efficient. No more waiting for lab results—investigations can move forward faster than ever.⁷

Portable sensors are also stepping up the game in detecting GSR, which is crucial for linking a suspect to a shooting. Electrochemical sensors now allow investigators to test for GSR on a suspect’s hands or clothing using a handheld device. These sensors detect elements like lead, barium, and antimony in just minutes—eliminating long delays and reducing reliance on lab testing.^3,8,9

Another breakthrough is laser-induced breakdown spectroscopy (LIBS), a technique that uses laser pulses to analyze the chemical composition of GSR. Recent improvements in portable LIBS technology—including better magnification and argon gas flow—have boosted its accuracy to over 98 %, making it just as reliable as lab-based methods. Even better, LIBS isn’t just for GSR detection—it can also identify trace materials like explosives and drugs, giving forensic teams even more valuable data on-site.^3,9

With these advancements, crime scene investigations are becoming faster, more efficient, and more precise. Portable sensors are helping forensic teams collect and analyze evidence in real time, cutting down delays and improving case outcomes.

Advantages of Sensors in Trace Evidence Collection

The integration of sensors in forensic investigations isn’t just about cool tech—it’s about solving cases more efficiently and with greater accuracy. These advancements are changing how forensic teams operate, making investigations faster, more precise, and less invasive. Here’s why they matter:

• Speed: With real-time data collection and analysis, forensic teams can make faster decisions, reducing delays in investigations. Time-sensitive evidence can be processed on-site, speeding up suspect identification and case resolution.^2-4
• Non-Invasive Testing: Traditional forensic techniques often require sampling methods that can alter or even destroy evidence. Sensor-based approaches, however, allow for non-destructive analysis, ensuring that crucial trace evidence remains intact for further examination.³
• Portability: Many modern forensic sensors are compact and mobile, allowing investigators to conduct in-field analyses rather than waiting for lab results. This is particularly beneficial for time-sensitive cases where immediate results are necessary.³
• Accuracy: By minimizing false positives and enhancing the reliability of forensic results, sensor technology strengthens the evidentiary value of collected materials. Advanced detection methods, such as spectroscopic and biochemical sensors, provide high specificity in identifying substances.^3,4

As forensic science continues to embrace these innovations, the integration of sensor technology will only become more refined, making investigations more effective and evidence collection more robust.

What’s Next? The Future of Sensors in Forensics

With portable sensors already making forensic investigations faster and more efficient, the next wave of advancements is set to push the boundaries even further. Emerging technologies like nanotechnology, artificial intelligence, and IoT-enabled sensors are enhancing forensic capabilities, making evidence collection and analysis even more precise and reliable.

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One major breakthrough comes from nanotechnology, which has significantly improved sensor sensitivity. These cutting-edge sensors can now detect microscopic traces of biological and chemical residues that were previously undetectable. By capturing even the smallest amounts of trace evidence, forensic scientists can build stronger cases with more reliable data.

At the same time, artificial intelligence (AI) is streamlining forensic data analysis by integrating machine learning algorithms into sensor systems. AI-driven forensic sensors can rapidly process large datasets, recognizing complex patterns in GSR distribution, blood spatter analysis, or chemical compositions. These systems not only speed up forensic workflows but also reduce human error, offering deeper insights that might be overlooked in manual analysis. For example, AI-enhanced mass spectrometry can differentiate between nearly identical chemical compounds, improving drug identification in toxicology reports.

Meanwhile, the Internet of Things (IoT) and wireless sensors are revolutionizing how forensic evidence is tracked and managed. IoT-enabled sensors provide real-time environmental monitoring at crime scenes, tracking temperature, humidity, and airborne particles to ensure biological evidence remains uncompromised. Additionally, digital evidence logs created through IoT systems help maintain chain-of-custody integrity by automatically recording who accessed forensic samples and when, reducing the risk of tampering or mishandling.

One of the most exciting applications of forensic sensor data is in augmented reality (AR) crime scene reconstruction. By overlaying sensor-captured forensic evidence onto digital models, AR allows investigators to interact with reconstructed crime scenes in three-dimensional space. For instance, AR can visualize bullet trajectories based on GSR spread, reconstruct break-in scenarios using microscopic fiber evidence, or simulate a suspect’s movements based on footprint analysis. This level of detail not only aids forensic experts but also helps juries and legal teams better understand the sequence of events.¹⁰

As these technologies continue to advance, forensic investigations will become even more precise, data-driven, and resistant to errors or contamination. 

The Challenges of Adopting Sensor Technology in Crime Scene Investigations

However, despite all their benefits, advanced forensic sensors don’t come cheap. High-end terrestrial LiDAR scanners can range from $20,000 to $70,000, while even handheld models cost between $5,000 and $18,000—an expensive investment for smaller law enforcement agencies.

Beyond the initial investment, agencies must also factor in maintenance, software licenses, and training costs, which add up over time and make it difficult to sustain these technologies in the long run. This financial divide creates a technological gap between well-funded and resource-limited law enforcement agencies, impacting the consistency of forensic capabilities across different jurisdictions.

Other than the cost, these technologies also require specialized training. Without proper knowledge, even the most advanced tools won’t be effective. Making these systems more accessible and affordable will be key to broader adoption in the forensic field.¹¹

Similarly, ensuring that sensor-based evidence meets legal and scientific standards for admissibility in court adds another layer of complexity. Forensic teams need to establish proper protocols and documentation processes to ensure that evidence collected with these tools holds up under legal scrutiny.

Keeping up with the rapid evolution of sensor technology presents yet another challenge. As new and improved sensors emerge, agencies must continuously upgrade their equipment and training, which can be both expensive and time-consuming. Additionally, integrating these technologies into existing forensic workflows is not always straightforward. Many law enforcement agencies rely on legacy systems, and ensuring compatibility with new sensor-generated data can be a technical hurdle. Advanced sensors also generate massive amounts of data, which can quickly overwhelm traditional forensic data management systems. Without the right infrastructure and analytical tools, agencies may struggle to efficiently store, process, and analyze the wealth of information collected.

Despite these challenges, sensor-based technology remains a powerful tool for enhancing forensic investigations. The key to overcoming these barriers lies in innovative solutions, such as shared resources, standardized training programs, and more affordable technology options. By addressing these financial, technical, and operational limitations, law enforcement agencies—regardless of their budget—can harness the full potential of sensor technology to improve case outcomes and advance forensic science.

Want to Learn More?

If you're interested in how technology is shaping modern forensic investigations, here are a few topics to explore:

• What is Forensic Science?
• Unlocking the Future of Forensics
• What Spectroscopy Techniques are Most Useful in Forensics?
• Measuring DNA Shedding: A New Tool in Forensic Science
• Body Farms; An Overview of Their Purpose in Forensic Science

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Journal Reference

1. University of Florida (2022). Trace Evidence: the Role in Forensic Science. https://forensicscience.ufl.edu/2022/10/14/trace-evidence-the-role-in-forensic-science/ Accessed on 24 Feb 2025.
2. Chiuri, A., Chirico, R., Angelini, F., Andreoli, F., Menicucci, I., Marcello Nuvoli, Cano-Trujillo, C., Montalvo, G., & Lazic, V. (2023). Crime Light Imaging (CLI): A Novel Sensor for Stand-Off Detection and Localization of Forensic Traces. Sensors, 23(18), 7736–7736. DOI:10.3390/s23187736
   https://www.mdpi.com/1424-8220/23/18/7736
3. Lazic, V., Andreoli, F., Almaviva, S., Pistilli, M., Menicucci, I., Ulrich, C., Schnürer, F., & Chirico, R. (2024). A Novel LIBS Sensor for Sample Examinations on a Crime Scene. Sensors, 24(5), 1469–1469. DOI:10.3390/s24051469
   https://www.mdpi.com/1424-8220/24/5/1469
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   https://pmc.ncbi.nlm.nih.gov/articles/PMC7659947/
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6. Bruijns, B., van Asten, A., Tiggelaar, R., & Gardeniers, H. (2016). Microfluidic Devices for Forensic DNA Analysis: A Review. Biosensors, 6(3), 41. DOI:10.3390/bios6030041
   https://pmc.ncbi.nlm.nih.gov/articles/PMC5039660/
7. Zhang, H., Liu, X., Wang, X., Yan, Z., Xu, Y., Gaňová, M., Tomáš Řezníček, Korabečná, M., & Neuzil, P. (2024). SPEED: an integrated, smartphone-operated, handheld digital PCR Device for point-of-care testing. Microsystems & Nanoengineering, 10(1). DOI:10.1038/s41378-024-00689-2
   https://www.nature.com/articles/s41378-024-00689-2
8. Detecting Gunshot Residue In The Field. (2012). Chemical & Engineering News.
   https://cen.acs.org/articles/90/web/2012/11/Detecting-Gunshot-Residue-Field.html
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   https://www.spectroscopyonline.com/view/portable-libs-paves-the-way-for-more-effective-gunshot-residue-testing
10. Chango, X., Flor-Unda, O., Gil-Jiménez, P., & Gómez-Moreno, H. (2024). Technology in Forensic Sciences: Innovation and Precision. Technologies, 12(8), 120–120. DOI:10.3390/technologies12080120
    https://www.mdpi.com/2227-7080/12/8/120
11. Tredinnick, R., Smith, S., & Ponto, K. (2019). A cost-benefit analysis of 3D scanning technology for crime scene investigation. Forensic Science International: Reports, 1(100025), 100025. DOI:10.1016/j.fsir.2019.100025
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