"Yes, Miss Samarra, I may have been desperate for money, giving me motivation to kill Truthsayer Merek, but here's two bags of money I suddenly got at the time of his murder to prove my innocence."When I first read Primrose's explanation of what had happened, I was struck by how easy it would be to upset Samarra's opinion of the motive for the murder. Just have Primrose produce the two bags of gold coins given to her by the old woman. Samarra's whole theory was that Primrose was desperate for cash to keep the library open. Yet here in her possession is coin enough to keep the library afloat indefinitely. The presence of this stash would also help substantiate the story about the old woman. Together with the chameleon scales, this should be more than enough to rid Primrose of any suspicion in the crime.
And yet, Dickon never mentions it after he hears of it, and certainly not in his talk later with Samarra. Strange. If he believes the coins would be confiscated as evidence, he never says it... or even thinks it.
What is also strange, is that no one else here on this thread seems to have mentioned this.
Doesn't really work now, does it?
Also, Primrose feels guilty and responsible. She doesn't want to admit to the presence of the woman unless she has to, and by the time the MC manages to force it out of her, he tries a different approach that is more constructive to the investigation long-term.