Richard Blake become number one suspect is the main plot in this book not Seamus and Max's relationship and their romantic relationship happened too fast.
As for the unsolved mystery behind all those attacks, it gets more and more complicated and I think the mastermind is Richard Blake from BIH security. He grew up in the same foster care with Brian and I wonder if Brian aka Scout is already move on from Everest aka Raptor and falls into Richard "Ricky" Blake's embrace because what Scout said to Max "For once in my life, there you are, accusing the only person who has always been there for me. Always protected me.” Further he said to Raptor "You have no right! I’m not a fucking toy you can just decide you want to pay attention to because someone else decided to it pick up." I already have bad feelings about it but I hope I'm wrong and Scout still can't move on, but then my gut telling me that he already did. F*ck, I hate it!
Too bad the 4th book will be about Michael aka Merlin not Scout and Raptor. I think Merlin's love interest will be very straight friend of Troy, Dane Acker.