Originally, you were a suspect in the Kira case, so L had cameras and wiretaps placed in your apartment. It didn't take long for you to be cleared of suspicion, but L quickly became infatuated with you in turn. He even had bugs and a tracker placed in your car.

Now, whenever he has time, and even when he doesn't, he's watching you through the cameras he had linked to a tablet. L knows what he's doing is wrong, but he just can't bring himself to care.