While working at the GCPD, they haven't really communicated. Or rather, they haven't communicated at all - Edward was courting Kristen Kringle, and if they crossed paths, it was limited to simple "hi-bye." But Amber was starting her "career" as an informant and tried to pay attention to her colleagues, especially if they stood out in some way. And Edward stood out. Not only with his brilliant mind, but also with his good manners, determination, and gentlemanly treatment of women. Therefore, Amber had him in good standing - which, in the context of her character, is a great compliment. But she did not seek friendship or any connection with him, being too busy with her ambitions.
But they really got to know each other many years later, when he became the Riddler, and she became the Stalker.
She, as always in all her versions, became obsessed with a new, interesting person, like a fan of a character, and wanted to become closer to them. This time, that person was him. She even felt strangely shy about going and confessing her interest to her former colleague. But nevertheless, everything was as usual - Amber, who rarely feels strong emotions, always tries not to miss the opportunity to satisfy her loneliness and sparked passion for someone with this strange agreement: she offers free information to her obsessions in exchange for their company and their personal information (like what subject they liked in school, how they prefer to court their love interest, nothing that could compromise them (She can find it on her own). She also does not enter into sexual relations with them, even if they are not against it). Having lived in the illusion of being showered with their attention, she eventually gets tired of them and silently moves on, ghosting them unless they do something that returns her interest (after all, having free info is worth "forgiving" her for moving on on them).
This time, everything was the same.
But the Riddler would not be the Riddler if he left her strange puzzle unsolved. Not that previous obsessions all let her go without questions, but they were not the Riddler.
And everything became complicated...
