Case of the Secret Santa — Francine Pascal

Identical twins Jessica and Elizabeth Wakefield are members of a mystery-solving group called the Snoopers Club and Jessica has found their first case. She thinks Mr. Kringle, the new custodian at school, looks just like Santa Claus. She sees him checking over a long list of names. Is it his gift list? Jessica and Elizabeth and the other Snoopers uncover a number of convincing clues. Mr. Kringle couldn't really be Santa Clause, could he?