The Summer of the Bear by Bella Pollen

From Library Journal: "In summer 1979, a bear touring the British Isles with its trainer slips off its leash and paddles through the waves until it reaches the Outer Hebrides. It's soon spotted by Jamie Fleming, an imaginative if slightly off-balance lad who quickly associates the creature with his father. Nicky Fleming, once a rising star in the diplomatic corps, died mysteriously while serving in Bonn and has since been suspected of being a traitor. His devastated wife, Letty, seeks respite by bringing Jamie and his sisters, dutiful Georgie and rebellious Alba, to the family's vacation spot in the Hebrides, once her own home. There, she tries to piece together what Nicky really did (or didn't do) and whether his fall from the embassy roof was accident or suicide, even as oddly assorted townsfolk drop by, Alba turns shoplifter, and Jamie, who's never -really understood that his dad is dead, comes to regard the bear as his savior. The mystery here is satisfying (and effectively resolved), but this is not a spy novel despite Nicky's calling. It's a sweet, affecting, well-wrought tale of a family torn apart and then reunited and will charm most fiction readers."