The Case of the Spurious Spinster (1963)

Dedicated to Richard O. Myers, Forensic Pathologist
Wealthy Amelia Corning, owner of the Corning mine interests, might be an old lady in a wheelchair but she doesn't miss a trick. Secretary Susan Fisher has to call in Perry Mason when she finds her boss's seven-year-old son holding a shoebox stuffed with hundred-dollar bills. Miss Corning's life is at risk.
“Your client’s guilty, Perry,” said Paul Drake, “And what’s more, I’m betting that within twenty-four hours Amelia Corning’s body will be discovered somewhere and you’ll find your client charged with murder.”
“She may be charged with murder,” Mason said, “but that doesn’t mean she’s guilty.”
“How can you say that? There isn’t a ghost of a chance she’s innocent.”
“That’s because you’re looking at the evidence from the standpoint of the prosecution.”
“Phooey! This is one case you’ve lost.”
“He hasn’t lost it yet, Paul,” Della Street said sharply. “He’s got an hour and thirty minutes before court reopens.”