The Silent Suspect — Carolyn Keene

RAGING FIRES OF MYSTERY!
Nancy's in San Francisco to help Ned's uncle, architect Robert Franklin, investigate a series of suspicious fires at one of his construction sites. Digging into the ashes, she uncovers one very disturbing clue: a bracelet belonging to Franklin's own daughter Lisa.

For reasons she won't reveal, Lisa refuses to explain the evidence against her. Although the police consider Lisa a suspect, Nancy is convinced of her innocence. Following a trail from Fisherman's Wharf to Chinatown, Nancy is determined to smoke out the true arsonist -- and save Lisa, THE SILENT SUSPECT, from herself.