The case of an unusual DNA analysis of fingernail clippings is described. A 20-year-old woman died of strangulation, and her former boyfriend entered the police’s sight as suspect through rapid investigation and inspection. Genomic DNA from debris scraped underneath the suspect’s fingernail was extracted 2 days after the incident using the modified DNA pretreatment method. Finally, mixed DNA profiles were observed from the suspect’s fingernail clippings, one of them originating from the victim, which is consistent with the result of criminal investigation. With the support of strong evidence, the suspect soon confessed. In this case, it was really unusual in practice that fingernail debris extracted from the suspect was used to accuse the suspect himself. This case demonstrates the usefulness of the modified DNA pretreatment method and the possibility of getting DNA profiles from fingernail clippings with 2 days’ lapse between the incident and recovery of the evidential material.