Sight Unseen — Robert Goddard

It happened in broad daylight -- the shocking abduction of a two-year-old girl at Avebury, an ancient stone monument in England. David Umber, a callow young student of history, saw it all. As fate would have it, the tragedy introduced David to the nanny who had been caring for the girl and her siblings. And for seventeen years David and Sally were together, until the weight of the past tore them apart -- and caused Sally to take her own life.

Now a retired policeman named Sharp has hunted David down. Even though a sex offender pled guilty to the crime, Sharp believes the truth is far from clear. And he has evidence: a taunting letter written in a style that only David, the would-be historian, can truly comprehend. Suddenly the two men are unraveling secret links between seemingly guiltless people...but the more they push and pry, the more they miss: that a suicide may have been a murder, that a killer may still be out there, and that what David saw with his own two eyes may be the most dangerous illusion of all...