An unknown mtDNA sample sample is matched to a sample of mtDNA that was found at the crime scene. This is how mitochondrial DNA (mtDNA) typing is used in forensic science.
Unlike nuclear DNA typing, mtDNA isolation is quite easy because its number is quite large. mtDNA copies rang from 100 to 10,000 per cell. It is also more stable and stronger than the nuclear DNA; that is why even unsolved cases from years ago use mtDNA typing as reference for possible conclusion.