Catherine Tramell is a fictional character and main antagonist in the film Basic Instinct (1992) and its sequel, Basic Instinct 2 (2006). Catherine, created by writer Joe Eszterhas, is played by Sharon Stone in both films. In Basic Instinct, Tramell is a serial killer and love interest of washed-up detective Nick Curran; Basic Instinct 2 pairs her with the similarly troubled British psychologist Michael Glass.

Is it true that was catherine tramell the killer in basic instinct?
yes