You bring in Leda and present her with the facts.

The DNA matches.
She had access to the truck
She had the tissue and movtive
She had a grudge against the triple-timing doctor.
She forged the order, and put the Maximine on the tissue
While she did so, her hair fell on it.
She gave the tissues to Sophia, then followed her to the park.

87% 6/10.

This is a very unsatisfactory ending - why did she call in the dead body? What was going on with that? But it turns out, this isn't the end. It's just the prelude to the last mission.

CSI Crime scene Investigation Walkthrough