Two Little Girls in Blue Mary Higgins Clark

Returning one evening after a party, Margaret and Steve Frawley discover that their three-year-old twin girls, Kelly and Kathy, have been kidnapped. A note demanding an eight million dollar ransom has been left in their room. Steve's firm agrees to pay and the kidnapper, who calls himself the "Pied Piper", makes his terms known - on delivery of the ransom, a call will come revealing the girls' whereabouts. The call comes, but only Kelly is in the car parked behind a deserted restaurant. The driver is dead from a gunshot wound and has left a suicide note, saying he had inadvertently killed Kathy and had dumped her body in the ocean. But all is not what it seems...