Murder? [short mystery]

It had always been her ritual, and Thomas, her husband, had tried to stop her without avail. No one could control the passion and the unfading desire within her that made her depart from the house that night.
The night that had enveloped a neighborhood along the Underground Railroad left her with a secure place to hide. No one saw her as she entered the beat up sedan quietly like a flock of runaway slaves, firing up the engine. Hard rock music muffled the noise; no one suspected a thing.
All she needed were the tools - where were they? She remembered the shiny metal knife in the kitchen of…