Perry Mason S08 E28 The Case of the Grinning Gorilla

"Almost anyone is capable of a crime under certain circumstances."

Della buys the diary of a drowned woman at an auction and after reading the entries becomes convinced that the woman's death was not a suicide as was ruled at the time. This leads Perry into a case involving an eccentric millionaire, his two scheming assistants, and a kleptomaniac gorilla.