Dead man's knock

the long version

DEATH BEHIND CLOSED DOORS Young and voluptuous Rose Lestrange walked into her bedroom and plunged a razor-sharp dagger through her heart. At least that's what the police said -- it would have been impossible for a killer to pass in and out of her bedroom because the windows and door were securely locked and bolted from the inside! ENTER DR. GIDEON FELL But master detective Dr. Gideon fell was never one to find the impassable impossible. He knew rose Lestrange had been savagely and brutally murdered, and if blackmail was indeed the motive, other lives were surely in danger. It was up to the indomitable Fell to latch onto the locked-room killer before he bolted for freedom -- and lock him away for good!