Some disjointed thoughts to put out there...
I found this to be compelling, but at first it felt like Tucker did less than his job out of residual anger at Elliot. Also, I would have liked to have seen more from Tucker's PoV, but it did fit in with Lanyon's usual style, so I knew I'd get something from Tucker eventually, and I did.
I liked the way he grew their relationship, even through the phone calls, where a lot got said by staying unsaid. But I also liked that Elliot recognized that Tucker made the first move to open himself up more often than not and so made the attempt, even though it went against his instincts and nature. There was excellent chemistry between them. I also liked that they were two strong men, but that they weren't afraid to show their vulnerabilities in bed.
Also really liked the dynamic between Elliot and his dad. Respectful and loving despite their obvious philosophical differences.
As far as the mystery, it was well done. I had hoped for some additional evidence gathering and to see that, but that's the thriller lover in me. It wasn't lacking, although I'd have liked some further explanation on the Baker murder.
Another stellar book from Lanyon.