This is book 4 of the "Mac McRyan" series.

This note contains spoilers for the book.

Interesting; he seems to have gone entirely to self-publishing. In my experience this is unusual for a New York Times and USA Today bestselling author (the other direction, self-publishing to conventional, gave us Andy Weir and a few others). Also he's pricing his books at $3.99 (ebook) on Amazon. The library doesn't have his latest, might be related (and the library is where I encountered him and gave him a try). (Although, come to think of it, Lois McMaster Bujold is self-publishing the Penric novellas.)

I got this in a "boxed set" (of ebooks) of three, this and the next two. Somewhere in there, there are a couple of things that remind me, once deliberately for sure, of John Sandford's Lucas Davenport books; which makes sense since Stelljes is also writing Twin Cities mysteries and Sandford is the big fish in that pond. One of them is just that Mac becomes wealthy from a small investment he made; something similar happens to Lucas. However, detectives who don't have to make a living give the author a lot of freedom, and famous examples include Sherlock Holmes and Lord Peter Wimsey, to go back a ways; it's not unusual (Nero Wolfe, on the other hand, works entirely for the money). The other is a quip about police officers who drive Porsches; that's what Lucas drives early on, but also what Matt Payne of Philadelphia drives (W.E.B. Griffin, Badge of Honor series).

This one again has a quite complicated plot, lots of events and shifts in views of things. At bottom is a plot to steal the presidential election by corrupting voting machines in a few key states; the murders were part of the security response and coverup for that. (And so, to draw a parallel with Stuart Woods, we now have Mac MacRyan knowing the president personally and his wife working in the Whitehouse; well, not in this book, they get married at the end of book 7.)

Weird holes in gun stuff, as usual—though more about gun laws than about the guns themselves, for a change. Or maybe recent former cops really do routinely ignore the fact that carrying without a carry permit is supposedly a serious crime. (And owning multiple handguns in DC without any legal authority! Oh, wait, that's a later book.) With Mac popping in and out of the police force, in and out of being an FBI consultant, etc., the legalities may be lagging anyway. He seems completely confident nobody will bother him, never thinks about it, but that's arguably just his career as a cop in a reasonably gun-friendly state influencing his attitude (or Stelljes not knowing how weird and draconian the laws get, or Stelljes simply not feeling like slowing down his plot to deal with a point few people care about).