Preliminary assessment of fingermark development techniques for recovering faint ridge impressions from persons with ectodermal dysplasia

Latent fingerprint collection and analysis remain a critical forensic technique in a variety of settings globally. However, the quality of deposited fingermarks depends on a plethora of extrinsic and intrinsic factors, one of which includes how skin diseases or conditions can affect development and recovery of latent fingerprint impressions. One such condition is hypohidrotic ectodermal dysplasia (HED), which involves underdevelopment of partial or complete absence of eccrine glands. This study aimed to establish whether recovered fingermark quality was different between HED-positive and unaffected control individuals, and whether quality of developed marks from HED-positive individuals was higher using chemical versus powder methods. Control and HED-positive individuals deposited fingermarks on three different substrates and two development methods were used per substrate . Developed fingermarks were scored qualitatively and compared statistically. Generally, HED-positive individuals produced significantly lower quality marks than the control group, and powder development (either standard or magnetic black) produced significantly poorer quality fingermarks than chemical methods across most substrates for both HED-positive and control group individuals. Taken together, these results support fingerprint examiners using chemical enhancement techniques preferentially where faint fingermarks are encountered. These results contribute important insight for improving best practice and maximizing evidence recovery from faint fingerprint impressions.