New spray-assisted method for development of papillary traces with fluorescent cyanoacrylate at room temperature. Operational devices for law enforcement forces – CYANOSPRAY

Forensic sciences are central to criminal investigations since uncovering, collecting and analyzing crime scenes evidences allows clear identification of suspects. Improvement of existing protocols is thus a field of intense research in forensic sciences. Dactyloscopy which is the science of fingerprint examination has emerged as one of the most powerful tool in criminal identification. However, the current technologies are limited to efficiently find out latent (invisible) deposits on crime scenes. The most advanced technique is Cyanocrylate fumigation which is widely used by law enforcement forces. However it is realized in a confined and controlled environment (fumigation chambers) and so limited to small and medium sized objects.
Lumicyano™ which is a fluorescent version of cyanoacrylate has recently been developed by Crime Science Technology Company and PPSM laboratory. It represents a strong technological advance in the field because, thanks to its intrinsic fluorescence, this product allows easier detection of latent fingerprint deposits on objects without the need of protocol modifications or use of toxic chemicals. Furthermore Lumicyano™ is compatible with DNA extraction and analysis. However, cyanoacrylate fumigation is still difficult to apply in the case of large volumes such as entire rooms even if precious marks may be present on walls, doors, windows…
The CYANOSPRAY project proposes to develop a more efficient and easy-to-handle fingerprint development technique by replacing the fumigation of the cyanoacrylate by its spraying. The project aims to produce an all in one transportable device that can carry out easy, safe, cheap and fluorescent revelation of latent fingerprints directly on crime scenes. In order to reach this goal, fundamental studies of the fumigation will be conducted first. Indeed, even if fumigation of cyanoacrylate is routinely used in forensic laboratories, its mechanism is still not completely known. From such a comprehensive study, the crucial parameters for fingerprint development with cyanoacrylate will be highlighted, allowing setting the proposed alternative method: spraying of cyanoacrylate. Its room temperature spraying will generate liquid droplets that deposit on surfaces and reveal in situ latent fingerprints. Thanks to this approach, it will also be possible to include in the cyanoacrylate formulation fluorescent dyes of various colors that only need to be soluble but not with low sublimation point as is the case in fumigation. This will lead to a range of accessible colors that can be chosen to maximize the contrast with colored substrates. A task will be devoted to the preparation and study of compatible dyes including testing on DNA. In a second step, and based on the fundamental results obtained, different devices will be designed and fabricated that fits the technical requirements. Then they will be tested in laboratory on model samples for technical validation. Finally, the devices will be given to end-users (French police forces) for a final operational validation.
In order to fulfill this ambitious project a high level consortium which combines all necessary competences has been gathered. The fumigation mechanism investigation and exploration of various spray process will be done by researchers from the Laboratoire de Chimie de la Matière Condensée de Paris at Collège de France (UMR 7574). The synthesis of fluorescent molecules and test of the devices will involve a research team of the laboratoire de Photophysique et Photochimie Macromoléculaires et Supramoléculaires at ENS Cachan (UMR 8531). PPSM will also coordinate the project. The fabrication and technical validation of the demonstrators will be carried out by the R&D unit of Crime Science Technology (SMB from Villeneuve D’Ascq). Finally, operational validation will be carried out in parallel by end users of the Institut National de Police Scientifique and Institut de Recherche Criminelle de la Gendarmerie Nationale.