Bloodletting(1997)

Serena Stalin wanted to learn from the best. So she tracked down Butch Harlow, one of the world’s most notorious serial killers, and blackmailed him into teaching her the fine art of murder. Now, as the lessons begin, teacher and bloodthirsty student unleash an unspeakable passion that forces them to kill over and over again, leaving a trail of horribly mutilated victims in their wake...