In the case of DNA evidence, it was of no use in this murder. DNA evidence can identify the killer by identifying the victim's blood on the killer's clothing or other effects if it had splattered during the act, or the killer's blood underneath the fingernails of a victim who had struggled, or a rapist's semen; DNA evidence confirmed that Anastasia had been inside Justin's car that night (from hair samples), but that was already known. Byron Case stood about two to three feet away when he shot Anastasia with a rifle, and no DNA was shared between killer and victim.

However, forensic evidence was gathered that showed Anastasia had not struggled with her attacker, nor had she tried to cover up from the fatal shot (indicated by no defensive wounds⁽¹⁾ and no tearing or disarray of clothing); this indicated that she had not been abducted, and had made no attempt to run from a pursuer. Forensic evidence also showed that the bullet that killed her hit her at a high velocity and from close range (indicated by the nature of the wound), and was much more likely a rifle,⁽²⁾ shotgun with a slug, or high-powered handgun than a standard .22 calibre handgun.

This forensic evidence was important in that it made clear the extreme unlikeliness of Anastasia having been attacked by a random killer, and also the equal unlikeliness of her having been killed with a .22 handgun.