The Last Kind Word

Rushmore McKenzie agrees to go undercover to help the ATF track a cache of stolen guns—after all, what could possible go wrong?
Rushmore McKenzie is both a millionaire and an unlicensed PI, which means he can afford to do the occasional favor and, as a former detective for the St. Paul (Minnesota) Police Department, he's got the necessary skills and connections to do them right. But this time, he's really stepped in it.
When the ATF gets a lead on a much sought-after cache of illegal guns near the Canadian border, they call McKenzie in to help them track down the elusive gunrunners. Their only lead is a guy who is part of a small-time gang of armed robbers working north of the Twin Cities. Their idea is for McKenzie to infiltrate the group and wait for them to lead him to the guns. Their plan is to fix McKenzie with a false identity as a serious bad guy and then fake an escape with the captured gang member. Which seemed like a bad idea to McKenzie at the time, but even he had no idea just how bad things were going to get.
Last Kind Word is a Twin Cities P.I. Mac McKenzie novel from David Housewright.