Keira Knightley

Loretta McLaughlin

Carrie Coon

Jean Cole

Chris Cooper

Jack Maclaine

Alessandro Nivola

Detective Conley

Rory Cochrane

Detective Deline

David Dastmalchian

Albert DeSalvo

Peter Gerety

Eddie Corsetti

Robert John Burke

Eddie Holland

Morgan Spector

James McLaughlin

Michael Malvesti

Detective Donovan

Nancy E. Carroll

Mary McDermott

Therese Plaehn

Kelly

Stephen Thorne

Frank Cole

Greg Vrotsos

George Nassar

Ian Lyons

Gordon Nielson

Christian Mallen

Paul Dempsey

Pat Fitz

The Killer

Pamela Jayne Morgan

Anne Samans

Robert C. Kirk

Arthur

Charlie Thurston

Fritz

Kate Middleton

Phyllis

Ivan Martin

Stanley

Kate Avallone

Lifestyle Editor

Tamara Hickey

Ellie

Luke Kirby

F. Lee Bailey

Thomas Kee

Richard DeSalvo

Kyra Weeks

Emmie

John Lee Ames

Harrison

James Ciccone

Detective Linski

Bill Camp

Commissioner McNamara

Jimmy LeBlanc

Officer Dougan

Gary Galone

Belmont Detective

Josh Drennen

Sergeant Burke

Brian Faherty

Officer Sullivan

Michele Proude

Anna Slesers

Grace Aiello Antczak

Claire

Rosemary Howard

Helen Blake

Kris Sidberry

Sophie Clark

Kate Lynch

Beverly Samans

Erin Rose

Assault Victim

Caitlin Zerra Rose

Young Woman

Paula Plum

Mrs. Quinn

Danny Connelly

Building Super

Frank Ridley

Ida's Super

Bill Mootos

Dr. Grayson

Jennifer Lafleur

Nurse Patty

Danielle Perry

Nurse Deb McNulty

Moira Driscoll

Psych. Orderly

Victor Warren

Director

Bill Thorpe

Brawny Detective

Mike Bash

Inmate

Marissa Carpio

Production Assistant

James Wilcox

Police Examiner

Michael Tow

JC Kim

Jonathan Fielding

Herald Reporter

Owen Burke

Officer Shanley

Al Conti

Boston PD Detective (uncredited)