A Bad Night in New Hampshire — Terry Boone

It begins on Lake Winnepesaukee and covers much of the Granite State. A suspicious death, the Presidential Primary, a bad actor in 'off the record' campaign fundraising, citizens with different views about some of the candidates, and the reemergence of a truly nasty character.
This is book # 3 in the New England based mystery series featuring Vermont Private Investigator Michael Hanlon and the undercover guy Louie Ragsdale. The first two books, A Cold Morning in MAINE
(2014) and A Quiet Evening in CONNECTICUT (2015), received wide and enthusiastic response from readers throughout the Northeast.