Stand up and die

She was such a beautiful blonde it was unfortunate, indeed, that she was dead when a handsome young Marine, just out of the service, met her on a lane in Westchester County. But —she had a younger sister, equally beautiful, and an invalid grandmother with an income tax in the upper brackets. Naturally, there was a doctor prescribing for for grandma, a lawyer ministering to the needs of mammon, and, shortly, Captain Heimrich of the State Police investigating murder. The young Marine did not get the situation well in hand. Grandma forgot her script and stood up to die. Whodunit? .. You'll be surprised.