Mickey Spillane's Mike Hammer (1958)

Letter of the Weak (1x36)

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Mike receives a desperate letter from Harris Stevens who claims that he's being held against his will in a mental hospital. The physician in charge refuses to allow Mike to see the patient, but Mike learns from a nurse that she suspects the charges are true. Mike's chances of springing his client take a turn for the worse when the nurse and the physician are found stabbed to death by a knife that Harris was making to use in a desperate escape attempt