Application of likelihood ratio and posterior probability density in sex estimation from level two fingerprint features among Hausa ethnic group

Abstract

Abstract Background In forensic sciences, the nature and variability of configurations of epidermal ridge minutiae has practically been explored in the evaluation and comparison of fingerprints, including partial fingerprints. The objectives of the present study were to determine the potential of fingerprint minutiae (level two features) in estimation of sex using likelihood ratio and posterior probability density among Hausa population. Secondly, to determine which of the minutiae have more of the estimation power compared to others. Methods A total of 420 thumbprints from 210 participants were analyzed. The minutiae density was determined within a circle whose diameter cuts 18 ridges and passing through the nucleus of the fingerprints. Posterior probability density and likelihood ratio were used to estimate the sex. Results The results showed that the median of minutiae count in males tends to be significantly higher in right ridge ending and ridge enclosure. Similarly, in the left thumb, the significantly higher minutiae count in males was observed in the ridge ending and ridge dot. In all the minutiae types, higher minutiae density favors males compared to the females. Likewise, in all the minutiae density, except for right ridge convergent and bifurcation and ridge ending, absence of any of the minutiae in the thumb favored female participants. Conclusion Increase in minutiae density was likely to infer males more than females. Ridge ending minutiae was observed to have higher discriminating power shown by higher likelihood ratio for sex inference among Hausa population.

Keywords

• Forensic science
• Minutiae density
• Likelihood ratio
• Sex inference
• Hausa ethnic group