Vespa Crabro. Andi Hayes Detective Series, #4

When duty-aka the office-calls, Detectives George Donovan and Andrew 'Andi' Hayes follow, albeit reluctantly. In Spartanburg, people are dying by arthropod, and the office sends Andi and George to investigate. At first, everything looks like a coincidence and well within statistical probability, but the deeper they dig, the blurrier and sinister everything becomes. And as if a chief hell-bent on protecting the reputation of his precinct and an FBI agent on the warpath weren't enough, George's mother has announced a family visit for his upcoming birthday.
Andi and George don't know what's worse: a string of nonsensical murders with leads sizzling away faster than spittle on the hood of a car on a hot summer day, or a mother in lioness mode determined to protect her "innocent" cub-George-from an "evil" menace-Andi. Finding their strength in each other might be the key to surviving both. Vespa Crabro is the fourth book in the Andi Hayes Detective series.
It's M/M, low on the romance (demisexual main character) and high on the murder, with a healthy dash of family drama, ghosts, and-of course-enough creepy crawlers to make the hair on your nape stand up. It does have an HFN, depending on one's definition of a happy ending for a story with multiple dead people in it. The main characters are reasonably happy, so that counts.right?