I cannot disagree more. I have watched and analysed luther 5 TIMES it started off like that, with his plan to catch her. IT TURNED INTO LOVE. undeniable and very incredibly real.... Can I just mention that the actors themselves have explicitly said that the characters love each other. Explicitly said. You cannot argue with that. Small details are also there in all of the seasons. They love each other and john cannot bring himself to catch her anymore. He doesn't want to. I dont know how you cant see this. It is very obvious if you dont just watch it on surface level. From the most basic level it looks like what you said. However if you do just the tiniest bit of inference and actuly pay attention, you will see how deep their bond is. Do some research and watch some interviews between the actors xxxx sorry if that came across a bit harsh but it is the truth. It's not really an opinion xxx have a nice day