Keira Knightley as Loretta McLaughlin

Carrie Coon as Jean Cole

Chris Cooper as Jack Maclaine

Alessandro Nivola as Detective Conley

Rory Cochrane as Detective Deline

David Dastmalchian as Albert DeSalvo

Peter Gerety as Eddie Corsetti

Robert John Burke as Eddie Holland

Ryan Winkles as Daniel Marsh

Morgan Spector as James McLaughlin

Michael Malvesti as Detective Donovan

Aurora McLaughlin as Maggie

Liam Anderson as Tommy

Antonio Volpicelli as Patrick

Nancy E. Carroll as Mary McDermott

Therese Plaehn as Kelly

Stephen Thorne as Frank Cole

Greg Vrotsos as George Nassar

Ian Lyons as Gordon Nielson

Christian J. Mallen as Paul Dempsey

Pat Fitz as The Killer

Pamela Jayne Morgan as Anne Samans

Robert C. Kirk as Arthur

Charlie Thurston as Fritz

Kate Middleton as Phyllis

Ivan Martin as Stanley

Kate Avallone as Lifestyle Editor

Tamara Hickey as Ellie

Luke Kirby as F. Lee Bailey

Thomas Kee as Richard DeSalvo

Kyra Weeks as Emmie

John Lee Ames as Harrison

Richard O'Rourke as Old Addict

James Ciccone as Detective Linski

Bill Camp as Commissioner McNamara

Jimmy LeBlanc as Officer Dougan

Gary Galone as Belmont Detective

David Conley as Old Desk Cop

Josh Drennen as Sergeant Burke

Brian Faherty as Officer Sullivan

Caroline Nesbit as Jane Sullivan

Michele Proude as Anna Slesers

Grace Aiello Antczak as Claire

Sheriden Thomas as Nina Nichols

Rosemary Howard as Helen Blake

Kris Sidberry as Sophie Clark

Sissy O'Hara as Ida Irga

Kate Lynch as Beverly Samans

Corinne Ognibene as Strangler Victim

Erin Rose as Assault Victim

Caitlin Zerra Rose as Young Woman

Laura Darrell as Karen

Lydia Harrell as Ms. Thompson

Paula Plum as Mrs. Quinn

Jake Casper as College Kid

Danny Connelly as Building Super

Frank Ridley as Ida's Super

Bill Mootos as Dr. Grayson

Jennifer Lafleur as Nurse Patty

Danielle Perry as Nurse Deb McNulty

Moira Driscoll as Psych. Orderly

Victor Warren as Director

Bill Thorpe as Brawny Detective

Mike Bash as Inmate

Marissa Carpio as Production Assistant

James Wilcox as Police Examiner

Michael Tow as JC Kim

Jonathan Fielding as Herald Reporter

Owen Burke as Officer Shanley

Al Conti as Boston PD Detective (uncredited)