DNA profiling is a forensic technique in criminal investigations, comparing criminal suspects' profiles to DNA evidence so as to assess the likelihood of their involvement in the crime. The ability of DNA profiling to link an individual to an incident, means that it is often a key element of forensic evidence in criminal cases. 

Since only a few cells can be sufficient to obtain useful DNA information, the list below identifies some common items of evidence that may be needed to collect, the possible location of the DNA on the evidence, and the biological source containing the cells.
EvidencePossible Location of DNA on the EvidenceSource of DNA
Baseball bat or similar weaponHandle, endSweat, skin, blood, tissue
Hat, bandanna, or maskInsideSweat, hair, dandruff
EyeglassesNose or ear pieces, lensSweat, skin
Facial tissue, cotton swabSurface areaMucus, blood, sweat, semen, ear wax
Dirty laundrySurface areaBlood, sweat, semen
ToothpickTipsSaliva
Used cigaretteCigarette buttSaliva
Stamp or envelopeLicked areaSaliva
Tape or ligatureInside/outside surfaceSkin, sweat
Bottle, can, or glassSides, mouthpieceSaliva, sweat
Used condomInside/outside surfaceSemen, vaginal or rectal cells
Blanket, pillow, sheetSurface areaSweat, hair, semen, urine, saliva
\"Through and through\" bulletOutside surfaceBlood, tissue
Bite markPerson\'s skin or clothingSaliva
Fingernail, partial fingernailScrapingsBlood, sweat, tissue