Okay, so this series was unique and intriguing for the first...maybe two books. Book 3 started getting repetitive and Book 4 hasn't gotten much better.
The whole capture and kill part of these stories are almost a carbon copy, two or three times in each book, and then from one book to the next. For each book there are only maybe a few pages of new material that is interesting and unique. I'm hoping that Part 5 rounds up the story or at least makes it more interesting with less repetition because this could be a great story, but it's just getting a bit boring at the moment.