1st to Die (2001)

Imagine a killer who thinks, "What is the worst thing anyone has ever done?"--and then goes far beyond it. Now imagine four women --a police detective, an assistant DA, a reporter, and a medical examiner --who join forces as they sidestep their bosses to track down criminals. Known as the Women's Murder Club, they are pursuing a murderer whose twisted imagination has stunned an entire city. Their chief suspect is a socially prominent writer, but the men in charge won't touch him. On the trail of the most terrifying and unexpected killer ever, they discover a shocking surprise that turns everything about the case upside down.