布莱恩·丹内利
Brian.Dennehy
饰：John Wayne Gacy
迈克·里雷
Michael Riley
饰：Lieutenant Joseph 'Joe,Polock' Kozenczak
玛戈·基德
Margot Kidder
饰：Rachel Grayson
梅格·福斯特
Meg Foster
饰：City Attorney Linda Carlson
Scott Hylands
Scott Hylands
饰：Delta Squad Sergeant Mike Paxton
戴维·艾斯纳
David Eisner
饰：Detective Terry Williams
John Boylan
John Boylan
饰：Detective Gary Atkins
托尼·德桑蒂斯
Tony De Santis
饰：Delta Squad Detective Craig DeMarco
Mark Humphrey
饰：Delta Squad Detective King
Gary Reineke
Gary Reineke
饰：Delta Squad Detective Leonard 'Lenny' Petrie
Tim Progosh
Tim Progosh
饰：Delta Squad Detective Jack Morris
Danny Pawlick
饰：Patrolman Tony Santori
布鲁斯·拉姆塞
Bruce Ramsay
饰：Forensic Officer Edward 'Ed' Bragg
布伦达·巴济内
Brenda Bazinet
饰：Alice Pearson
Liliane Clune
Liliane Clune
饰：Marcia Kozenczak
托比·普罗克特
Toby Proctor
饰：Michael Kozenczak
Christopher Marren
饰：Billy
Gerry Quigley
Gerry Quigley
饰：Detective William 'Bill' Walden, Intelligence Officer
Nicholas Pasco
Nicholas Pasco
饰：Detective Gil Barton
迈克尔·科普曼
Michael Copeman
饰：Police Chief Wallace 'Wally' Cameron
James Kee
James Kee
饰：A.D.A. Don Hoskins
杰伊•布兰泽
Jay Brazeau
饰：Jake Burns
辛西娅·普雷斯顿
Cynthia Preston
饰：Cindy Beck (as Cyndy Preston)
Andrew Gillies
Andrew Gillies
饰：Vincent Austin
Kurt Reis
饰：Waterloo Police Chief Waldron
Judith Goodwin
饰：Mrs. Gant
肖恩·劳伦斯
Shawn Lawrence
饰：Mr. Gant
Maureen McRae
饰：Mrs. Trask
蒂姆·泽马內克
Timm Zemanek
饰：Mr. Trask
Maria Ricossa
Maria Ricossa
饰：Helen Gacy
Darryl Palmer
饰：Grundy County Sheriff
Peter Langley
Peter Langley
饰：Mr. Miklovich
John Friesen
John Friesen
饰：Detective #1
Ray Paisley
饰：Illinois State K-9 Officer
布雷特·哈尔西
Brett Halsey
饰：Stan Wilder
大卫·加德纳
David Gardner
饰：Judge
David Bolt
David Bolt
饰：Asst. Principal Burke
Thomas Hauff
Thomas Hauff
饰：Foreman Hendricks
J. Winston Carroll
J. Winston Carroll
饰：Sergeant (Wabash Ave.)
Don Ritchie
Don Ritchie
饰：Detective (Shakespeare Ave.)
Rudy Webb
饰：Cemetery Staff Member
艾略特·史密斯
Elliott Smith
饰：Young Gas Station Attendant
Robbie Rox
饰：Cicero Bar Owner
Larry Reynolds
Larry Reynolds
饰：Finger Lake Proprietor
Jon Granik
饰：Narrator
路易斯·古兹曼
Luis Guzmán
饰：Waiter (uncredited)
Jacqueline Samuda
饰：(uncredited)
Martin Julien
Martin Julien
饰：Theodore 'Ted' Koslo
Brigette Lawson
Brigette Lawson
饰：Pam
Jacqueline Graham
Jacqueline Graham
饰：Lorna Gant
Nicholas Shields
Nicholas Shields
饰：Christopher 'Chris' Gant
Sarah Gibney
Sarah Gibney
饰：Lisa Kozenczak
Aviva Magner
Aviva Magner
饰：Debbie Kozenczak
David McAree
David McAree
饰：Older Worker
Veliko Pajkovic
Veliko Pajkovic
饰：Young Man at Bus Station
Peter Kerenyi
饰：Pool Player (uncredited)