texasag

Correction: Interesting, but I am not sure I can pinpoint which part of the final reveal suggests he knew she was innocent 'all this time'? The day after the murder, he expected to see her accused of the homicide and therefore invalidate the part when she'd inherit. Instead, he hears that it's been ruled as suicide, and hires Blanc to uncover 'the truth', because suicide would be terrible for him, she'd get all the money. So he thought Blanc would reveal that he was killed by Marta, not that she was innocent. And when he got the vials back (which he needed to do anyway), he was seen by Fran, making necessary for him to kill her and implicate Marta either way. If you mean that during their conversation he figured out that she was innocent, Marta -does- say in her story and it is repeated at the end, that she thought she mixed the two vials up when they fell. So when they speak, he takes that as a fact and realises that if she really did accidentally give him the 'wrong' vial, she gave him the right one.

Sammo ★

Correction: Actually Ransom does know that Marta gave Harlan the correct dose of the meds, at the time of the interview at the diner itself. Because Marta was forced to tell the truth to Ransom about how she mixed up the meds. Now, Ransom knows that he switched the contents of the vials. So when Marta says that she switched the vials themselves, Ransom figures out that because he switched the contents of the vials, the effect of his action of trying to poison his grandfather was nullified. The fact that Ransom knew about the innocence of Marta, is not dependent on her ability to tell the meds apart by their viscosity and tincture, but on the fact that Ransom figured out of the nullification of his act of mixing up the contents of vials.