I Tell C is one of those mangas that draws you in with an interesting gimmick but struggles to use it properly throughout the series. I think something similar would be Promised Neverland, that starts off strong as a thriller, mind game series and ands up as a generic action series. In I Tell C the gimmick is that our MC is a stalker of criminals, she falls in love with a perp and finds more info on them by stalking them. The stalking is related to an incident in her past that is the driving force of the story and we get little bits of info after each case.

However, by the second case the gimmick has already run its course. The stalking lasts all of one chapter, and the deductions are completely hidden from the viewer. Usually in a good crime drama you want to sprinkle clues and suspects throughout several chapters so that the audience can play along. In I tell C, she will always have the case solved from the beginning because stalking requires you know who you're stalking.

Another issue is the secondary characters, black cop and white cop. Neither are important to the cases. White cop sits at his desk saying how much he distrusts MC girl, and black cop will come in and karate chop the suspect as they're about to kill her. Neither of them are interesting or add anything to the story. Any screentime wasted on them debating "using poison against poison" could be used to build an interesting case or show some stalking.

By the third case, MC has given up stalking. We meet the killer straight away, we have a mysterious author who is likely another killer/rival character, and the cops continue to be useless. Sad to say this manga is definite axe bait, I really enjoyed the concept but it does nothing with it. I'm hoping future cases are longer and we get to see the stalking process more, and that the criminals are left in the shadows a bit longer.

Recommendation: Just read Red Dragon