1. Sith are after power, and killing a bunch of people doesn't really serve her in any way.
2. It's usually easy to sense when a Force user kills someone.
3. The wounds were made by a regular knife, not a lightsaber.
4. She was the one to tell us about the bodies.
5. Some of the corpses were extremely decomposed; they'd probably been there for months, if not years, before she even arrived.
6. Most importantly, I trust her. Saying that she's a killer because she found bodies is like saying you're an Imperial for finding Qorl.
What'd she do to make you worry? Because she was taught by Anakin Skywalker? Do you suspect Master Obi-Wan for teaching him, or Master Qui-Gon for finding him? Do you suspect me, for being named for him?