Down a Dark Road by Linda Castillo

When she was young, Kate worshiped neighbor Joseph King. They lost touch after he moved away following his father's death, when both Kate and Joseph were teenagers.  Now, she gets word that he has escaped from prison, where he is serving a life sentence for murdering his wife, Naomi. Joseph's children now live with Rebecca and Daniel Beachy, Naomi's sister and her husband, so Kate decides to notify them of Joseph's breakout, since they are Amish and don't have a phone. Kate finds herself caught in the middle when Joseph arrives at the Beachy's while she's there and takes his children hostage. Joseph also tells Kate that he did not kill Naomi and asks for her help in finding the her killer. Kate decides to look into the case, putting both her career and life on the line.