Preliminary investigation of the ability of fingerprint examiners in detection of sib-sib relationships based upon finger and palm prints similarities

Variations in biometric parameters such as fingerprints between populations, genders and even twins are wide-ranging issues routinely examined by the forensic community. In this study we tested whether fingerprint examiners can detect if finger and palm prints originate from siblings. In total, 410 finger records and 300 palm records of siblings and non-siblings were examined by seven certified forensic fingerprint examiners with different levels of qualifications and experience. The examiners were asked to determine, based on friction ridge characteristics, if they could detect similarities to such a degree that it was possible to declare a familial relationship (FR) between two prints. The results indicated that among all seven fingerprint examiners, 'true negative' values were very high (95–98%), meaning that in cases where FRs were absent, the examiners' decision was usually correct. In cases where FR was declared by the expert, the probability of a 'true positive' was 25 and 10 times higher than the probability of a 'false positive' for finger prints and palm prints, respectively. We attempt to elucidate the specific fingerprint parameters which facilitate better sibling detection, and conclude that sibling detection by fingerprint similarity may have potential as a novel forensic tool that can be used for intelligence operations.