Whiskey Beach by Nora Roberts

Whiskey Beach - After a year of defending himself against the charge of murder for the death of his wife, Eli Landon has moved into Bluff House in Whiskey Beach.  The home has been in his family for over 200 years and his grandmother, recovering from injuries due to a fall, asked him to live in the house to keep it open while she recovers in Boston.  Abra Walsh, his grandmother's housekeeper, involves herself in his life to bring him out of his depression.

Although the Boston PD has been unable to find evidence of Eli's guilt, lead Detective Wolfe is obsessed with Eli and finding that evidence.  After a PI's death in Whiskey Beach, Wolfe is even more determined to pin the murders on Eli.    Meanwhile, Bluff House has been broken into and Abra is attacked when she walks in on the intruder.  The Eli and the local police believe it has something to do with the legend of a lost treasure related to the house and Whiskey Beach.