Ragan, Theresa. Sawyer Brooks series #4

"On her first day of kindergarten, five-year-old Tinsley disappeared without a trace... Five agonizing years later, her divorced mother, Dani Callahan, is a private investigator. She and Quinn Sullivan, a promising young assistant determined to prove herself, are devoted to helping others find missing loved ones. And for Dani, finding Tinsley is still a never-ending obsession. Their newest case is Ali Cross, a teenager who vanished off a Sacramento street while walking home. A troubled boy's eyewitness testimony to Ali's abduction provides their only clues. And as their search for Ali gets underway, new information about Tinsley's disappearance begins to surface too. As their investigations lead down two twisting paths, disturbing secrets are revealed and new victims find themselves in mortal danger. Time is running out, and the hunt is only getting grimmer"--Back cover