Cold Case Files: REOPENED – "Mr. Big Sting"

Podcast: Cold Case Files
Host: Paula Barros (voice talents include Doug Dupe, investigators, and witnesses)
Date: September 4, 2025
Case: The 1992 Murder of Marie Dupe, Cape Breton, Nova Scotia

Episode Overview

This episode of Cold Case Files investigates the 1992 murder of Marie Dupe in Cape Breton, Nova Scotia, a case that confounded investigators for nearly a decade. The episode details the painstaking investigation, complicated by harsh winter weather and rumors, and the eventual use of an elaborate undercover operation known as the "Mr. Big" sting, which elicits a confession from the perpetrator, Ernest Gordon Strowbridge.

Key Discussion Points and Insights

Setting and Victim Background

• Cape Breton Setting: The episode opens with a vivid description of Cape Breton's natural beauty, traditional music, and close-knit community ([00:05]).
• Marie and Doug Dupe: Recently retired to Cape Breton, seeking a slower, peaceful life ([00:48]–[01:00]).
• Marie's New Job: Marie, growing bored in retirement, takes a job at the local Big Bend convenience store ([01:00]–[01:33]).

The Crime and Initial Investigation

• The Night of the Murder: On March 21, 1992, Marie works her first night shift during a blizzard. She is murdered during her shift ([01:33]–[02:34]).

• Discovery: A local man finds Marie alive, but critically injured, lying in blood at 4am ([02:34]).

  • Sergeant Jim McLean:

    "I walked down to the back of the store and I could see that this lady was brutally stabbed. Her throat was slashed, the side of her face was slashed, her right ear was severed right off. She had blood, it seemed to me, coming out of everywhere. I was horrified." ([02:34])

  • Despite efforts, Marie dies an hour later due to blood loss.

• Crime Scene Challenges:

  • The blizzard ruined potential footprints or tracks outside.
  • Melting snow inside the store compromised evidence, mixing water and blood ([03:18]–[03:32]).
  • Key Evidence: Multiple cigarette butts collected for future DNA analysis ([03:41]).

Early Suspects and False Leads

• Doug Dupe Investigated: Doug is initially a suspect, especially after his resigned comment on seeing the police ([04:20]).
  • Doug Dupe:

    "Right off the bat I says, 'My wife did. What else could be the bad news?'" ([04:20])

• Community Rumors: The investigation is muddied by unfounded rumors of drug dealing and “mafia ties” ([04:57]).

Evidence and Witness Testimony

• Discovery of the Knife: As snow melts, the bloody knife used in the murder is discovered outside the store ([06:12]). It was a store sandwich knife stained with Marie's blood.

• Store Receipts and Witnesses:

  • Police track every transaction from Marie’s shift, interviewing customers ([06:51]).
  • One significant, unidentified sale at 3:16am for cigarettes.
  • Witness at 3:18am:
    • Customer describes a man acting strangely—statue-like, unresponsive except to smoke or sip coffee. He deeply unsettled the witness and Marie ([07:22]).
    • Sketch generated, noted for the suspect’s “dead” and “deep” eyes ([07:45]).

Case Goes Cold, Then Heats Up

• Years of Investigation: Despite hundreds of interviews, police cannot locate the man matching the witness sketch ([08:26]).
• DNA Breakthrough:
  • In 1997, DNA testing capabilities allow the cigarette butts’ DNA profile to be uploaded to a national database.
  • In 2001, a match is found: Ernest Gordon Strowbridge, who lived nearby at the time and has since moved ([08:56]–[09:12]).

The Mr. Big Operation

• Need More Than DNA:
  Detective Glenn Bowmaster:

  "All the DNA did was put him in the crime scene. It's a pretty big stretch from putting someone in the crime scene to saying he committed the murder." ([09:33])

• Undercover Sting:

  • Police use the "Mr. Big" technique: Strowbridge is drawn into a fake criminal gang and ultimately meets the “boss” (Detective Bob Deasy) ([10:31]).

    • Setup: Strowbridge thinks he’s interviewing for a role in a crime family; must confess a serious crime as a sign of loyalty ([11:00], [11:42]).

  • Confession:
    Strowbridge confesses openly:

    "There was a thing called the big Benz murder... It was a convenience store... I didn't realize I'd done it until, like, the next day because I blacked out. And then when I woke up next day, I was covered from at the toe and black... There was a murder there. Yeah. And I done it." ([11:52])

  • Detective Deasy’s Reaction:

    "That really took me aback. And I then had to think backwards from that point because essentially we began with the climax." ([12:43])

  • Strowbridge (on why he confessed):

    "The only reason why I told you is because... you know, it's part of the trust. Trust relationship part. I appreciate that." ([13:21])

Arrest and Resolution

• Strowbridge Arrested: He is then confronted by Detective Doyle, who informs him everything was taped.

  • Strowbridge soon admits the truth in the police interview, expressing some regret ([13:32]).

• Legal Outcome:

  • Strowbridge pleads guilty almost a year later. As he was a juvenile at the time, he receives a life sentence with a possibility of parole in seven years ([15:18]).

• Doug Dupe’s Reaction:

  • Doug Dupe:

    "No, it's not enough. No. He did his first 12 years not being caught. That was his parole. Guy should be doing life right now. But I'm glad it was before I went to my grave myself because it's nice to see it settled." ([15:55])

Notable Quotes & Memorable Moments

• “Her right ear was severed right off... I was horrified.” — Sgt. Jim McLean ([02:34])
• “All the DNA did was put him in the crime scene. It’s a pretty big stretch… to saying he committed the murder.” — Det. Glenn Bowmaster ([09:33])
• “I didn’t realize I’d done it until, like, the next day because I blacked out.” — Ernest Gordon Strowbridge ([11:52])
• “The only reason why I told you is because... it's part of the trust.” — Strowbridge ([13:21])
• “Guy should be doing life right now. But I'm glad it was before I went to my grave myself.” — Doug Dupe ([15:55])

Key Timestamps

| Timestamp | Segment | |-----------|-------------------------------------------------------------------| | 00:05 | Introduction, Cape Breton background | | 01:33 | Marie Dupe’s murder and discovery | | 02:34 | Sgt. McLean's description of the crime scene | | 03:41 | Evidence gathering—cigarette butts | | 04:20 | Doug Dupe informed, initial police suspicion | | 05:11 | Police clear Doug, rumors abound | | 06:12 | Discovery of murder weapon | | 07:22 | Witness recounts seeing suspect, description for police sketch | | 08:56 | 2001 DNA match: Ernest Gordon Strowbridge | | 09:45 | Plan for an undercover “Mr. Big” sting | | 11:52 | Strowbridge confesses to crime boss (audio) | | 13:32 | Strowbridge confesses again after arrest | | 15:18 | Sentencing, Doug Dupe reflects on justice and closure |

Takeaways

• Forensic Breakthroughs: Modern DNA analysis can revive 'cold' cases even after a decade.
• Undercover Police Tactics: The “Mr. Big” sting is controversial yet effective in eliciting confessions when direct evidence is lacking.
• Community and Grief: The episode illustrates the ripple effect of violent crime in close-knit communities and the emotional journey for victims’ families seeking closure.
• Justice and Closure: Family members may struggle with sentencing outcomes, even in successful prosecutions.

Cold Case Files underlines how perseverance, scientific advances, and creative investigation techniques can bring resolution—even decades after a murder.