Case Study: Digital Voice Technology
Written by Sandi Schnorenberg   


WHEN KEY EVIDENCE in a homicide investigation almost slipped away, the decision was made by the Mankato Department of Public Safety police staff in Mankato, Minn. to switch from analog to digital voice technology.

During the investigation of a 2010 homicide (an extremely rare occurrence in the city of 40,000 residents), a crucial, incriminating portion of an interview session recorded at the police station was inaudible due to the poor quality of the analog tape and the low volume of the suspect’s mumbling voice.

With the case put in jeopardy and the climbing expenses and inefficiencies associated with analog tape, the police staff eventually implemented digital voice technology that included handheld recorders, dictation microphones, and workflow management software. The voice technology not only helped officers and administrative staff work more efficiently, but the department was also able to reduce transcription expenses and create clearer, higher-quality recordings that stand up to scrutiny in the courtroom.

Analog tape and equipment proves unreliable

Mankato Department of Public Safety serves a population of approximately 80,000 residents, college students, visitors, and commuters who work at its major health center and state university campus. Mankato’s 51 police officers respond to approximately 150 calls per day, of which as many as 10 require in-depth reports with multiple witness and suspect interviews or lengthy incident descriptions.

For many years until the early 1990s, the department’s police officers created all their reports using a dictation system that was based in the station. When the antiquated system proved too costly and ineffective at capturing crucial data, the officers transitioned to typing shorter reports and recording longer statements and interviews on desktop recorders that used standard-sized analog cassettes.

As years passed, the cassettes grew more expensive and difficult to procure. The recording equipment was also so undependable that the department needed to purchase an additional machine as a backup for the interview room. In addition, finding qualified technicians to fix analog machines became increasingly difficult or not even worth the expense.

Workflow challenges compiled, as well. Transcribing the cassette tapes was an inefficient process where the transcriptionist, who worked off-site, needed to pick up cassettes daily at the station. Due to the limited recording quality of analog tape, the transcriptionist often needed to rewind and re-listen to several passages to ensure accuracy. If an officer requested that a report be fast-tracked, the transcriptionist would need to search the cassette until the relevant statements or interviews were found.

The turning point for digital voice technology

A Mankato Department of Public Safety officer utilizes one of the dictation microphones installed at the Public Safety Building’s computer workstations. Officers use the system to dictate reports at the end of their shifts. The completed recordings are centrally stored and transcribed with workflow-management software.

Minnesota law requires that all police questioning, not just confessions or statements, be recorded. During the 2010 homicide case that led to the switch to digital, this law proved to be crucial to the investigation because the suspect had verbally implicated himself in the crime—not during direct questioning, but when he was alone in the interview room mumbling to himself.

Although the case was still closed, Mankato’s city manager demanded the Department of Public Safety upgrade to digital voice technology so the same situation would not be repeated. Mankato is also the largest city in its county, serving a growing resident and transient student population, so modernizing the police staff’s evidence-gathering equipment was a prudent investment.

The department considered and tested devices from numerous companies, but made a final selection based on simplicity of operation, structural durability, and integration with workflow-management software.

Training police officers to use the new technology was a rapid process, even for those who were reluctant to transition to digital. Facilitating the adoption was that the handheld recorders’ functionality was nearly identical to the analog devices, except officers did not need to be concerned with saving or transferring cassette tapes for transcription.

Speech recognition streamlines reporting

In 2014, the department purchased 35 dictation microphones for cruisers and for the station so officers could take advantage of speech recognition software. Dictation is automatically transcribed using the software as the officers speak into the microphone.

Initially, the department purchased 45 handheld recorders for officers to conduct dictation in the squad car or the police station. In 2014, Mankato Department of Public Safety purchased 35 dictation microphones for cruisers and for the station so officers could take advantage of either device’s compatibility with speech recognition software. Dictation is automatically transcribed using the software as the officers speak into the microphone, whereas the handheld recorder uploads dictations to a laptop or desktop computer or server to be transcribed later.

Integrating speech recognition into the officers’ workflow required some training, as well. The software needs to learn the unique characteristics of the speaker’s voice, which requires slower, more deliberate dictations when the technology is introduced. However, modern speech recognition software adapts and learns much faster than technology from even just a few years ago, so the adjustment did not greatly impact officer productivity or report quality.

To support the speech recognition software integration, the department’s voice technology vendor helped configure the electronic records-management system so officers could dictate and transcribe directly into the incident report template and also move the cursor around the screen using the buttons on the dictation microphone. Now, when officers are on the other side of town, they can complete the report from their current location, eliminate travel time back to the station, and still be a presence in the community in their squad car.

Improving suspect questioning and witness statements

At the police station, the replacement of analog tape recorders with a digital dictation microphone in the interview room has greatly improved not only the recordings’ sound quality, but also the questioning sessions. Working with another voice technology vendor, the department strategically installed the dictation microphone in the room so it would not distract the person being questioned, but it would still be able to capture all the spoken words, even if mumbled. The dictation microphone that the department chose is decoupled from its housing which prevents background, touch, click, air, or structure-borne noise from being recorded, further adding to the clarity.

Dictation microphones were also implemented in the Public Safety Building computer workstations where officers dictate reports at the end of their shift. These completed recordings from the workstations, as well as the interview room, are centrally stored and transcribed with the workflow-management software.

On that system, officers each have a dedicated folder where recordings are automatically routed after completion. If a transcription needs to be prioritized, the transcriptionist can easily identify and access the urgent recording on the software, instead of searching through an analog cassette tape. The transcriptionist can also securely access a dictation off-site, which is less expensive for the department and enables faster report creation.

The transition to a more efficient voice technology workflow has allowed the department to eliminate $35,000 in outside contractor transcription costs, as well as expenses associated with analog recorder repairs and cassette tape purchases. Most importantly, the sound quality of the digital recordings has helped the officers support city and county attorneys with building stronger criminal prosecutions.

About the Author

Sandi Schnorenberg is the administrative commander for Mankato Department of Public Safety.

< Prev   Next >

New Books

Bloodstain Pattern Analysis

Most forensic disciplines attempt to determine the “who” of a crime. But bloodstain pattern analysis focuses on the “what happened” part of a crime. This book is the third edition of Blood-stain Pattern Analysis. The authors explore the topic in depth, explaining what it is, how it is used, and the practical methodologies that are employed to achieve defensible results. It offers practical, common-sense advice and tips for both novices and professionals.