From The Perry Mason TV Show Book
This strange episode begins when Della buys the diary of a drowned woman at an auction. After reading the entries, she becomes convinced the woman's death was not a suicide, as the authorities ruled at the time.

The mystery thickens as Perry gets involved and discovers that there is a kleptomaniac gorilla on the loose, one who is later suspected of murder.

Gavin MacLeod and Victor Buono are featured. Janos Prohaska plays the gorilla.