The Medusa Pool by M. K. Wren (Amazon affiliate link): https://amzn.to/2pKvEUZ
"Election day in Wesport, on the magnificent Oregon coast, changes everything for Deputy Cornelia Faith Jones, the only woman and the only African American in the Taft County Sheriff's Office. As a result of a write-in campaign that Neely did not encourage, she is elected Sheriff --a job she did not want.
Neely accepts, however, when Jan Koto's body is found submerged in the jellyfish display tank in the Oceanographic Center. The victim is marine biologist Jan Koto and Neely's lover.
Grief and rage drive Neely to find Jan's killer, and she learns the hard way that small towns are not exempt from racism, rape, violence, and murder --and greed. When ex-sheriff Giff Wills is also murdered, Neely discovers she is dealing with a wide-ranging conspiracy." ~ On Amazon