Doom Magnet by Gregory Ashe

They say bad things come in threes. Usually, they don’t mean murder.

After several months (and a few murders), Dash is finally starting to feel at home in Hastings Rock. He’s enjoying the quiet after the end of tourist season, he’s comfortable at Hemlock House (the jury is still out on whether it’s haunted), and most importantly, he has friends.
Friends, unfortunately, who have a tendency not to take no for an answer. Which is how Dash finds himself at a cold-water surfing competition only a few days before Halloween—and, even worse, attending a costume party at the surf camp later that evening.
When Dash stumbles across the body of a predatory local real estate developer, he’s the only one who believes it’s murder. Worse, Dash’s friend Deputy Bobby (they’re just friends, thank you very much) is on leave from the sheriff’s office while he and his fiancé prepare for their move to Portland. But Dash is determined not to let a murder go unsolved. And as Dash works to prove that the death was anything but accidental, the killer turns their attention to him.