No Orchids for Miss Blandish by James Hadley Chase
When Dave Fenner is hired to solve the Blandish kidnapping, he knows the odds on finding the girl are against him - the cops are still looking for her three months after the ransom was paid. And the kidnappers, Riley and his gang, have disappeared into thin air. But what none of them knows is that Riley himself has been wiped out by a rival gang - and the heiress is now in the hands of Ma Grisson and her son Slim, a vicious killer who can't stay away from women, especially his beautiful new captive. By the time Fenner begins to close in on them, some terrible things have happened to Miss Blandish . . .