Fingerprints are crucial in any crime scene investigation as they are an impartial and objective form of evidence. As every fingerprint is unique, it can link individuals to specific crimes and incidents. Therefore police officers and crime scene investigators are required to document them at the scene of the crime with absolute care and precision.

The current fingerprinting process is not entirely linear. Fingerprints documented on-site are physically transferred to the forensic lab, where they can be analysed and compared to the prints in the database. In some cases, victims of a crime scene are requested to submit their prints down the line in an investigation to rule their prints from potential suspects effectively. This non-linearity leads to longer investigation processing times. Additionally, on-site investigators lack analysis capabilities which could support and validate their intuition and decisions in the field.

IMPRNT is a new breed of forensic tool for police and crime scene investigators to find and capture relevant fingerprints digitally. It allows investigators to gather fingerprints from crime scene victims with a built-in ultrasonic fingerprint scanner. The investigators can then utilise IMPRNT's multispectral illumination capabilities to examine latent fingerprints on objects and surfaces. The device performs a real-time comparison between the fingerprint under observation and those collected from the victims, which facilitates the investigators in efficiently pinpointing unidentified prints, which may be crucial to the investigation. These relevant fingerprints are digitally documented on IMPRNT on a 1:1 scale. Digital documentation enables contactless fingerprinting, reducing the chances of errors while collecting prints resulting in high-quality forensic evidence.
IMPRNT's ability to identify the relevancy of one fingerprint from multiple fingerprints, often from various individuals, on-site dramatically reduces the amount of evidence that needs to be processed, leading to quicker investigation processing times and a streamlined fingerprinting process.

Along with its contactless documentation capabilities, IMPRNT is a comprehensive fingerprint detection and digital documentation solution for police and crime scene investigators.

Introduction:

IMPRNT was a 10-week collaboration between the Crime Scene Investigation Team at Umeå Police Station, the Police Education Unit at Umeå University and the Umeå Institute of Design. During this project, we have identified relevant design opportunities and developed solutions for the crucial phase of any investigation involving a scene of a suspected or confirmed crime, the examination, documentation, collection, preservation and initial analysis of traces and evidence on-site.

Structure of the Swedish Police:

Securing evidence on-site at a crime site can, if it is a minor so-called "everyday crime", can be done by police officers responding to the call. Specialised crime scene investigators do this in case of a severe crime. In Sweden, the collected evidence is sent to the National Forensic Centre, NFC, an independent expert organisation within the police authority responsible for forensics. The structure of different law enforcement agencies might vary slightly across the globe, but IMPRNT is designed with Universal functionality in mind.

Human-centred design process:

The project started with field research at the Police Education Unit and Umeå Police Station to understand the tasks and responsibilities of Police officers and crime scene investigators. Hearing the on-site experiences of investigators highlighted the fact that the victims of the crime scene also need careful consideration in the design process for it to be genuinely Human-centric. Field Research Trip Video: https://vimeo.com/643467441

Design opportunities:

Police officers and crime scene investigators are required to identify relevant fingerprints at a crime scene as they could link a suspect to a location or an object. Presently, investigators use their intuition, experience, and information gathered from the victims to locate these relevant fingerprints with the help of powerful light sources. In certain situations, the victims involved could be requested to share their prints on-site using an ink pad to differentiate them from a potential suspect's print. They might also be asked to submit their prints at the station later in the investigation to eliminate them from the suspect's print. After a fingerprint of interest is located, a digital backup of the print is secured with a phone/digital camera as a safeguard in case of errors while performing physical documentation. Documentation of the relevant fingerprint requires the investigators to use various analogue tools to obtain a physical output of fingerprints on an adhesive tape or a casting material. These documented fingerprints are ultimately sent to the forensic lab, which takes 1:1 scale examination-quality digital pictures of them. These pictures are used for comparison and analysis. Once the images are clicked, the physically documented materials are discarded.

Introducing IMPRNT:

IMPRNT introduces a new workflow by equipping the on-site investigators with a fingerprint analysis tool which assists them in identifying relevant fingerprints already on-site with increased accuracy and efficiency. It replaces traditional fingerprinting with modern technology capable of direct digital documentation, eliminating the laborious process of using analogue tools.

Benefits to the Primary users:

The traditional ways of fingerprinting require police officers and crime scene investigators to perform laborious tasks like dusting fingerprints, mixing casting material multiple times, and tediously lifting fingerprints without errors while juggling various analogue tools simultaneously. The lifted fingerprint is then attached to a documentation card that is filled manually with case details and information about the print, like where it was lifted from and its orientation. IMPRNT digitises the whole documentation process through the multispectral imaging system, which can reveal latent fingerprints on various surfaces without using powders or chemicals. Its contactless documentation capabilities, like the documentation hood and 3D scanning ability, make IMPRNT capable of procuring accurate images in the correct scale without disturbing the evidence surface, even from complex surfaces. Digitised contactless fingerprinting also makes the fingerprint available for other forensic analysis processes like DNA sampling, checking drug traces, etc. It reduces the complexity of the fingerprinting process allowing investigators to share their focus on other aspects of an investigation. Multispectral imaging also makes the device capable of revealing different types of evidence like semen, blood, urine, saliva and gunshot residues.
IMPRNT brings analysis capabilities into the hands of on-site investigators. With their consent, victims can share their prints with the investigators enabling IMPRNT to highlight unidentified prints at the crime scene. IMPRNT also performs latent-to-latent fingerprint matching on the crime scene, which can help in understanding the movement of a suspect on the crime scene or the order in which particular events might have conspired.

Benefits to all Stakeholders involved:

IMPRNT reduces the on-site investigation time by assisting investigators in identifying potential evidence quicker. It also eliminates the time required to perform tedious physical documentation processes. Additionally, it saves the time needed to physically post the evidence to the forensic lab. As IMPRNT brings analysis prowess to the field, the volume of evidence which has to be processed by forensic labs reduces by a large extent as irrelevant forms of documentation like double-documentations and evidence belonging to known elements like the victims are already weeded out. The use of IMPRNT not only saves time for on-site personnel of law enforcement like police officers and crime scene investigators but also accelerates the further investigation process involving analysts at forensic centres, which leads to faster processing times for law enforcement systems. Therefore IMPRNT proves to be a time-saving and resource-optimising solution which is lucrative to various law enforcement agencies around the globe.

Designed to be Upgraded:

IMPRNT is designed with upgradeability in mind to adapt to changing technologies with time. The front module of the device, which hosts the multispectral imaging system, has a provisional space to add on upgrades. Its portable design allows the future possibilities to use the device with augmented reality solutions. With time, the entire front module, which holds the high-tech aspects of the product, can be replaced with advancing technology. All these factors contribute to ensuring the longevity and relevancy of the product over a longer period of time, making it a logical investment for law enforcement agencies.

Designed with the Users:

The feedback sessions with users through mockups indicated that the investigators would prefer a compact form that could be operated by one hand while the other is free to help them navigate the crime scene. Therefore, IMPRNT resembles the portability and compactness of the service flashlight they already use. It also allows for ease of manoeuvrability through tight spaces. IMPRNT's contact area, when rested on any surface, is minimised, as investigators are often required to put their tools down to attend to other tasks. This ensures that any potential evidence on the surface the device is placed on never gets disturbed.

Influence of the Human-centered approach:

Sharing fingerprints is a sensitive topic, especially at a crime scene where the victims might assume that they are the ones being incriminated. Therefore, the officers can request the victim's fingerprints only after explaining how IMPRNT helps to eliminate innocents from gathering evidence, ultimately saving time and enabling the investigators to focus on the relevant leads from the beginning. IMPRNT challenges the traditional workflow of investigations and allows victims to participate in the investigation process from the start. IMPRNT's digital fingerprint scanner does not leave ink marks on the victim's finger. In most cases, the victims might not even be required to visit the police station to submit fingerprints as the relevant fingerprint has already been detected on-site. Ultimately, the decision to share fingerprints is entirely up to the victims. This subject's sensitivity has been thoroughly considered during the design process to make IMPRNT be perceived as a participatory tool to the victims rather than an investigative tool. For the investigators, it is a non-intrusive way of incorporating smart tech into investigations as it only assists them in making informed decisions.

As mentioned earlier, submitting fingerprints is a sensitive subject, even after the victims have consented. When the investigators gather prints from victims, the victims can see the screen, giving them a sense of transparency in the process. A bi-directional UI assists this two-way interaction. The fingerprint scanner is built-in into the screen, making it easy to keep clean. The form of the product enables it to be held by the investigators in a 'requesting' gesture, reinforcing the feeling of trust for the victims.
The dark grey colour ensures the device signifies precision, high quality and confidence to the investigators while appearing non-threatening and approachable to the victims. The front module of the product, which is black in colour, is the product's high-tech section that is not visible to the victims while gathering prints. This ensures that already traumatised victims don't feel intimidated.

A Step towards Digital documentation:

IMPRNT promotes the move towards digital documentation. Traditional fingerprinting makes use of materials like dusting powders, adhesive tapes and casting materials and physically documented prints are secured on a documentation card that is sent to the forensics lab for further processing via post. Digital documentation eliminates the dependency on all physical elements and the need to transport evidence from scene to lab, making the forensic investigation process relatively more sustainable.