Two Novel Methods for Enhancing Postmortem Fingerprint Recovery from Mummified Remains

Abstract

Postmortem fingerprint collection is a routine part of many forensic death investigations. Although the production of postmortem prints is usually straight forward, several obstacles and scenarios can make the collection difficult. A common challenge occurs when finger pads are mummified. Several current techniques allow for softening and rehydration of mummified finger pads; however, despite the employment of such techniques, the production of adequate postmortem fingerprints can remain elusive. The authors present two techniques that can improve the chances of obtaining suitable fingerprints from mummified remains. The "baby powder method" involves applying a cornstarch-based powder, such as baby powder, onto the darkened and mummified finger pads, to allow better visualization of the fingerprint detail. The "transillumination method" involves carefully dissecting away the tissues underlying the finger pad, followed by placement of a bright light source underneath the finger pad, such that the finger ridge pattern is illuminated.

Papaya and pineapple juices facilitate rehydration of mummified dermal tissue for fingerprint capture

“…Although use of NaOH facilitates distension of finger volume by disrupting tissue integrity, thereby allowing fluid to be pumped in, its corrosiveness is damaging to epidermal tissue structures. This can compromise print quality and impedes forensic identification of decedents [9]. In comparison, fruit extract treatments enhance finger volume expansion without disrupting the integrity of features that are essential for ink‐based or digital fingerprinting methods (Figure 2A,B).…”

MÉTODOS DE IDENTIFICAÇÃO POST MORTEM EM NECROPAPILOSCOPIA FORENSE: revisão de literatura

“…Como modo de otimizar a fotografia direta, Morgan et al (2019) propõem uma abordagem que pode melhorar as chances de obter impressões digitais adequadas a partir de restos mumificados. Denominado de "método do talco de bebê", essa técnica envolve a aplicação de um pó à base de amido de milho, como, por exemplo, talco para bebês, nos dedos escurecidos e mumificados (Imagem 4).…”

“…Finalmente, uma fotografia ou macrofotografia da polpa digital pode ser produzida subsequentemente, devendo ser feita rotação horizontal (espelhamento) em editores de imagens, para fins de adequação da posição do datilograma com o padrão ante mortem (Imagem 5). Os autores explicam que o pó aderente nas cristas de impressão digital resulta no aumento dos sulcos intervenientes da crista papilar, produzindo assim o que parece ser uma "imagem negativa" de uma impressão digital com tinta (MORGAN et al, 2019). As possibilidades de uso da fotografia são vastíssimas e podem auxiliar tanto no campo forense quanto em trabalhos arqueológicos.…”

“…... Morgan et al (2019), visando o aperfeiçoamento da fotografia direta, propuseram a denominada "técnica da transiluminação". A técnica é indicada para dedos mumificados e consiste na remoção da polpa digital e colocação de uma fonte de luz brilhante por baixo do tecido epitelial, de forma que o padrão da crista seja iluminado, ficando apta para o registro fotográfico (MORGAN et al, 2019).…”

Rehydration and restoration of fingerprint ridge detail in mummified post‐mortem tissue: Literature review and investigation of a simplified formulation

“…Different rehydration and restoration approaches have been used to address these challenges dependent on the unique circumstances of each case. Non‐destructive techniques have shown some success and include taking impressions [6, 7], photography, or scanning [8, 9]. Often the cadaveric condition renders the aforementioned approaches insufficient, and destructive techniques involving physical or chemical processes, alone or in combination, are required to rehydrate the tissue and restore ridge detail.…”