Into the Deep, Rock Harbor Mystery Series by Colleen Coble and published by Nelson.
A canine search-and-rescue team find the missing link between disparate crimes that have authorities perplexed. A local scientist misses his son's birthday party and turns up dead in Lake Superior. A radical environmental group blames a mysterious lab for dead fish found in a remote stream. Then an Alzheimer's patient goes missing and his home is ransacked. Bree Nichols and her beloved search-and-rescue dog, Samson, pitch in to help investigate the events disrupting their small community. But new discoveries soon throw her shaky love life into tilt, dredge up her painful past, and threaten her family. Bree must dive deep for the faith to keep going, the strength to defend those she cares about, and the courage to keep her fearful heart open to love.