OK, you're back in the lab.

dirt - cactus soil matches pants
tissue - used, white powder traces, Maxamine
hair - doesn't have vic's sample yet
tire print - L160 pickup 70% match together

Head on over to the Morgue.

cancer? no
maxamine? she had uber histamines, garden stroll could have killed her
dna? yup

Return to the lab again. Sure enough, the victim's DNA matches the tissue. However, it doesn't match the hair, though. Whose hair is it?

Your theory is that the killer, who dropped a hair into the tissue, gave her the tissue laced with Maxamine to kill her

CSI Crime scene Investigation Walkthrough