Everyone saw that her explanation was bang on and couldn't help but wonder, how did she know?
The cop asked her in Dawnstar language, seeing as this is odorless and tasteless, how did she figure out Molly got hit with HN2C?
Rosemary answered in fluent Dawnstar, she deduced it from Molly's pulse. She checked Molly's pulse just now, and it was exactly like what someone poisoned by HN2C would have.
Generally, people struck by this poison felt intense stomach pain, so painful that they passed out. When they woke up, the pain spread to their limbs, they passed out again, and when they woke up, the pain spread all over.
This process lasted for three days; normal hospitals can't figure out the cause, and painkillers didn't work.
This HN2C was developed by some small country, specifically for torture, so she had no idea how it ended up on the streets.