Mobile Evidence Collection
Written by Detective Kerry Daniels   


Cramped. Disorganized. And outdated. Until recently, these would have been the words used to describe the Maplewood Police Department’s property room in St. Louis, Mo. Over the last 40 years, more than 6,000 pieces of evidence—from drugs to guns to bicycles and even a tombstone—were housed haphazardly in a 4 x 10-ft. space.

The Maplewood Police Department is a law enforcement agency with 31 officers and about 9,000 pieces of evidence. In early 2009, the chief challenged the department to bring order to the evidence room by implementing procedures for the orderly tracking, storage, and retrieval of evidence with the hope of attaining the ultimate goal: accreditation by the Commission on Accreditation for Law Enforcement Agencies (CALEA).

To make that goal a reality, the department made two important investments: 1) The headquarters recently underwent a space renovation and 2) purchased a mobile barcoded evidence collection software system, eTWIST, with both backend and tablet-device capabilities.

Headquarters Renovation

In 2009 the city of Maplewood renovated the police department, and one of the centerpieces of the effort was an overhaul of the evidence room. The small closet was replaced with a space four-times larger—12 x 24 ft. Movable shelving was installed to make the most of the expanded space. A pass-through lock system, including a refrigeration unit for the storage of fluid and DNA evidence, helps keep evidence secure. And whereas the old evidence room was too small to accommodate even the evidence properly, the new space is large enough for a processing desk where officers can log in evidence.

Mobile Evidence Collection Software

Mobile evidence collection devices can tag GPS coordinates along with satellite numbers used, providing exact data that can be used in court.

In an effort to bring order to their chain-of-custody capabilities, the Maplewood Police Department upgraded to a bar-coded/RFID mobile evidence collection software solution from St. Louis-based Primary Marking. The department considered other systems, but saw value in eTWIST’s front-end or mobile software system that allows the department to fully record and document the evidence chain of custody on a durable mobile device. The mobile device is integrated with Win Mobile or HTML 5-browser based software.

The handheld device operates like a smartphone but offers specialized applications designed with an evidence technician in mind. Officers can enter all of the same information in the field that would normally be entered while sitting at a desk. CAD/RMS data can be auto-populated in one device, further reducing errors and time spent collecting and entering redundant information.

One of the features that has served the department well is the ability to calculate measurements for solids, liquids, gases, and currency quickly and easily right in the field. Equally important is the ability to capture images of witnesses, suspects, victims, prisoners—along with aliases, physical descriptions, and their relationship to the evidence.

Barcodes: Not Just for Grocery Stores

The idea that the same barcoding technology used in grocery stores could also be used to track evidence made immediate sense to the evaluation team at the Maplewood Police Department. Until that time, the department had been using handwritten notes in the field, which could come back to the station either illegible, wet, or jumbled among several pieces of evidence. Now, there is a barcode that is unique and has the functionality of a vehicle license plate. After scanning all of the barcoded evidence, the labeled piece of evidence is placed in an evidence container. A “parent” label—consisting of all the respective tagged evidence, including each item barcode and a human-readable description of the item—is printed and affixed to the evidence bag for easy scanning and tracking. This tracking system has saved the department countless man hours, and translates to more officer time on the street.

Exploring Alternative Technologies

Similar technology is developing for use on some consumer-grade tablet devices. However, the evaluation team noted that consumer-grade devices can present power issues, such as reduced battery life and the inability to swap out a dead battery with a fresh one. These types of products are also not rated for use in flammable or potentially combustible or explosive situations. While consumer-grade tablets most certainly appear more economical, they lack the additional configurations required to endure the rigors of crime scene documentation, such as being dropped into a muddy field or creek at the crime scene. Often the collection of evidence demands officers to be onsite long hours, at night, in rain, below-freezing conditions, or high temperatures and humidity in areas where cellular or Wi-Fi connections do not exist.

Additionally, mobile evidence-collection software and devices require enhanced levels of security that are not available on consumer tablet devices.

Officers use an all-weather barbell (or “jewelry tag”) label that can be applied directly to the evidence, without compromising evidence integrity. This also eliminates the possibility of evidence or files being lost and disorganized in transition to the station, courthouse, or another location.

One challenge faced by many departments is losing track of who submitted evidence. Just do an Internet search for “bungled evidence” and it becomes clear how widespread this problem is, especially as trials drag through the courts. The system utilized by Maplewood Police Department alleviates this problem, requiring dual authentication inputs—the officer’s department service number or badge number, and PIN—coupled with the case number, time, and date, providing an accurate chain of custody for all transactions.

An internal camera on the handheld device has helped the department pinpoint the exact location where evidence was collected. Now, intricate details of the scene are captured by the internal camera or by other external audio and photographic recording devices. The compass heading, barometric pressure, temperature, and wind direction when the picture was taken are all recorded. The officers also record GPS coordinates for the evidence location, including the exact number of satellites and the satellite numbers with which the software connected. The GPS coordinates are valuable in court, as the location of the evidence is “collaborated” by at least three different satellites.

Byrne Justice Assistance Grant

To keep the evidence room overhaul on track, the Maplewood Police Department has applied for an Edward Byrne Memorial Byrne Justice Assistance Grant (JAG). In 2009, the U.S. Department of Justice unveiled the JAG Program that assists state, local, and tribal efforts to prevent or reduce crime and violence.

With Primary Marking’s assistance, the department is seeking funds to purchase additional handheld devices for the department. The process was simpler than anticipated, and the department expects to have an answer later this year.

CALEA Accreditation Process

The Maplewood Police Department is seeking accreditation by CALEA; the evidence-handling overhaul is an important part of that effort. As part of the rigorous accreditation process, the ability to retrieve evidence promptly is key. Before the renovation, the grant, and new evidence collection system, delivering evidence so quickly would have been an almost impossible task. There is now a place for everything and everything is in its place. The department is able to instantly locate evidence, track its location, audit it, control electronic evidence sharing or guest viewing, and purge and destroy old evidence.

Electronic tracking of evidence benefits the entire community and the Maplewood Police Department looks forward to this type of technology becoming the norm. Because this system is ideal for sharing evidence, the agency hopes additional departments move toward technology-based tracking solutions.


Today’s economic pressures are having rippling effects, creating budget reductions and rising costs—forcing federal, state, and local governments to search for a means to better contain inefficiencies, improve accuracy and increase conviction rates… all without impacting the quality of services. To reduce costs, governments must determine how to do more with less: how to enable fewer officers to manage the existing workload while also adjusting to increases in workload. Moreover, to protect the health and safety of their citizens, governments must strive to prevent the occurrence of human error that becomes a possibility the moment the evidence collection process begins—and continues into labs and evidence rooms.

Technology-based solutions for evidence collection addresses these issues by eliminating the hidden inefficiencies and opportunities for error in today’s law enforcement processes, enabling dramatic increases in productivity, data accuracy, and departmental cost savings.

Documentation, strong chain-of-custody procedures and proper storage of evidence are all crucial parts of the justice system. Without proper evidence, convictions are difficult to obtain. Tainted or poorly stored evidence can also mean the difference between conviction and acquittal. The department values the efficiencies provided by state-of-the art evidence-management techniques.

About the Author

Detective Kerry Daniels has served as the evidence custodian for the Maplewood Police Department in the St. Louis, Mo. area for the past nine years. He is instrumental in the evaluation, selection and implementation of mobile-based evidence collection methods. Daniels has been in law enforcement since 1999 and is a graduate of Lindenwood University.

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