City Under One Roof by Iris Yamashita

Cara Kennedy, a police detective from Anchorage, comes to Point Mettier, Alaska, to investigate some body parts that have washed up on the shore. It's October, the end of the tourist season, and in Point Mettier all 205 residents live in the same high-rise building, nicknamed Dave-Co. In addition, the only way you can get into town is through a tunnel that sometimes has to close because of bad weather. Cara is working with a local detective, Joe Barkowski on the case. Cara keeps it a secret that she has a personal reason for her interested in the crime. Soon, Cara finds herself trapped in Point Mettier, unsettled by the isolation and having to reveal why she's really in town. Will Cara and Joe be able to solve the case? City Under One Roof is the debut mystery by author Yamashita and looks to be the start of series.