Comment by Alcoholic Crusader on I Was Supposed to Be a Stalker Lady, but Somehow I'm Being Adored Instead - Chapter 19

@Alcoholic Crusader it's not that simple to the audience it's Rosaline. But for them the puzzle isn't complete, like the content of the conversion with Rosaline. Rosaline might have red hair but she could simply pin that on anyone like Marinette (maybe they don't have smth that identifies DNA in that world)...and lastly what's her motive for doing it. To me she doesn't like the crown Prince from my perspective seems like she wants seravi to always rely on her... Like let her be beneath her.

@Callmheizzy I mean yeah but at the same time some clues feel to Obvious and some factors like how she acts and talks are just well Obvious. In my opinion but fair point.

@Callmheizzy  
cant the ml just make them speak like what he did to fml in the forest?

@Jack Yoff yh, but he first needs to know the suspect which he doesn't yet and the fml won't tell him it's the red haired girl.

@Callmheizzy yeah but he thought fml did it so why didnt he just ask her "did you kill her" and then he can investigate and find the real culpri

@Callmheizzy yeah but he thought fml did it so why didnt he just ask her "did you kill her" and then he can investigate and find the real culprit

@Jack Yoff what no. That was his initial thought then as she was at the death. But he long since investigated and came to the conclusion it doesn't make sense for her to be the suspect, so he basically doesn't have any leads for now.

@Callmheizzy in the early chapter when she was fasting he called her a murderer, Im assuming he got the dragon tounge thing when he slayed the dragon which was mentioned to have happened earlier, so how come right after she was poisoned, use the truth thing to clear the most obvious suspec

@Jack Yoff well like the vice commander stated the compound in the cup was found on the mariette dress not on seravi so there's no logical explanation for her being the culprit hence why using that ability for didn't make sense i guess.. 
This is how the whole suspect stuff eventually happens after mariette death, he called her a murderer after the incident that was then, but he still doubted Mariette committed suicide and his first suspect was still seravi but the facts went against it added the fact that she's a stalker didn't make her look less innocent in the prince's perspective till the reincarnator took possession of her body things changed. Hence why he showed her his memories and asked "who do you think the culprit is?" And she states "for someone who suspects me his demeanour is rather gentle" implying he already discarded her being the suspect after she reincarnated