Ya investigué las 3 pistas pero las pistas descubiertas no aparecen en la ventana de la sección de pistas encontradas.
Con Samarra le hablé del veneno y me dio otra pista (que no lo olió y solo se lo bebió, si es eso entonces ya lo tengo).
Con Primrose no puedo hablar de las ventanas, sólo me sale lo de los libros.
Con el hechizo para descubrir secretos (quién es el culpable, pero es un hechizo avanzado).
If you have gotten the extra clue from Samarra already, then you have everything you need.
You need to have trained with the crone twice in order to reveal large secrets, that is a prerequisite for doing any of this.
The clue interface has more than one page, if you aren't seeing the ones you need, try the next/previous page of clues. All the ones for Primrose's large secret will appear next to each other on the same page. At least some of the clues vanish once you've revealed her secret.
Once you have the clue Samarra gives you, all you need to do is visit Primrose and cast invade mind. Pay attention to the dialog, it will give you pretty clear hints about which of the 4 clues you need to present when.
Once you have revealed her secret and have ended the spell, Primrose shows you a secret room in the library and you get a clue for revealing Samarra's large secret - which is what you need to do to keep Primrose out of jail. The rest of the clues you need for that involve
searching behind the library, and asking the crone about what you find there - but you cannot do any of that until after you've revealed primrose's secret.