Dr. Robert Elliott

Robert Elliott  aka Bobbi is true main villain of 1980 film Dressed to kill

About
Robert Elliott was respected psychiatrist who dreamt to become a woman someday however his male side refused his wish caused breakdown and where  woman sexually aroused which Robert feel threatened and become serial killer. one of patients Kate Miller was unhappily married mother to her son Pete, talk him about her sexual experinces with men and having affairs, as she tried seduce him but Elliot rejects her advances, trigged him as Bobbi track down Kate who contacted sexually transmitted disease from one night stand and slashed her to death which call girl  Liz Blake witness thus become killer's next tagert