from the cloth fibers oscar noticed stuck to kara 's teeth , and the lack of blood devin found in the nail holes that bored through the frozen dirt under her hands and feet , they assumed the following : she 'd been killed at another location after the killer had shoved a handkerchief or piece of shirt in her mouth , then made an incision in the base of her throat with either a stiletto or a very sharp ice pick to demobilize her larynx .