'The Crossing Places' by Elly Griffiths
The bones actually turn out to be 2,000 years old but Ruth is soon drawn into the Lucy Downey case and into the mind of the letter writer, who seems to have both archaeological knowledge and eerie psychic powers. Then another child goes missing and the hunt is on to find her.
The Crossing Places is the first in the Ruth Galloway series. Click here to see the author's website for a description of the series and her other writing.
The Cleveland Park Mystery Book Club meets on the first Thursday of the month, 6:30 p.m., at Barnes & Noble, 12th and E streets NW.