Scent of Murder — Cynthia G. Alwyn

Brenna Scott is the founder of a volunteer search team in Sacramento, California, a group of people with their specially trained dogs ready when needed. When a series of children go missing, however, the team is pitted against an especially clever and deeply evil opponent.
Brenna is horrified when the kidnapper makes contact with her via email. As the disturbing game escalates in intensity, children continue to disappear, and the search dogs keep their noses to the ground. Everyone hopes the canine crime fighters will turn up a clue before it's too late. These amazing animals proceed with loyalty and dedication and their training and talents prove instrumental in solving these horrendous crimes.