General · EdgepediaOctober 3, 20266 min read

Trial 4

Trial 4 (French title Le quatrième procès) is an eight-part Netflix documentary series, released on November 11, 2020, that follows Sean K. Ellis, a Boston man who spent over 21 years in prison for the 1993 murder of Boston Police Detective John J. Mulligan and fought to prove his innocence while exposing police corruption in the investigation¹^•². The series was directed by Rémy Burkel, written by Burkel with Jean-Xavier de Lestrade, and produced by What's Up Films in coproduction with Gaumont Télévisions³. Its title refers to the fourth trial Ellis was preparing for when filming began; that trial never took place, because prosecutors dropped the charges in December 2018⁴.

Key fact	Detail
Format	Eight-part documentary series, episodes of roughly 52 to 60 minutes, total runtime about 7 hours 4 minutes⁵
Release	November 11, 2020, on Netflix, in the United States at 8:00 AM GMT¹
Director and writers	Directed by Rémy Burkel; screenplay by Rémy Burkel and Jean-Xavier de Lestrade³
Production	What's Up Films, in coproduction with Gaumont Télévisions³
Subject	Sean K. Ellis, convicted in 1995 at his third trial for the 1993 murder and armed robbery of Boston Police Detective John J. Mulligan; the first two trials ended in hung juries⁶
Outcome covered	Charges dropped in December 2018; the remaining 1995 firearm conviction was thrown out in May 2021⁴^•⁷
Reception	Metascore 79 on Metacritic; 100% on the Rotten Tomatoes Tomatometer; 7.5/10 on IMDb⁸^•⁹

Spoilers

The case the series documents

Sean Ellis was 19 years old when Boston police arrested him in October 1993 for the killing of Detective John Mulligan, who was shot to death while working a paid detail at a Walgreens in Roslindale¹⁰. Ellis had spoken voluntarily to police about the murder of two of his cousins in his Dorchester neighborhood days earlier, and was arrested hours after their burials¹¹. He was charged with armed robbery and first-degree murder; Mulligan, 52, was shot five times in the face with a .25-caliber pistol while sleeping in his SUV, and his service weapon, a 9mm Glock, was stolen¹².

Ellis's first two trials ended in hung juries on the murder and armed robbery charges, and he was convicted at the prosecution's third attempt in 1995, along with a firearm conviction from the first trial⁶^•¹³. He served 21 years, 7 months, and 29 days in prison while maintaining his innocence¹¹.

Corrupt investigators. The investigation was led by Boston Police detectives Kenneth Acerra, Walter Robinson, and John Brazil, who secured witnesses and physical evidence in the case⁶. Acerra and Robinson pleaded guilty to federal corruption charges in 1998, in a scheme involving robbing drug dealers, and Brazil was granted immunity in exchange for his testimony¹²^•⁶. It was later determined that the victim, Detective Mulligan, had participated in those criminal schemes with his colleagues¹³.

In 2015, Suffolk Superior Court Judge Carol Ball ordered a new trial for Ellis, writing that his defense attorney, Rosemary Scapicchio, had discovered new evidence suggesting corruption within the investigation of Mulligan's homicide itself, including withheld exculpatory evidence⁶^•¹². Ellis was released on bail that year¹². In December 2018, acting Suffolk County District Attorney John Pappas announced that Ellis would not be retried, saying the current state of the evidence made it unlikely the prosecution would prevail in a new trial, while Pappas and Police Commissioner William Gross maintained that Ellis was guilty⁴^•¹⁴.

The case did not fully close with the series. In March 2021, District Attorney Rachael Rollins filed a motion supporting a new trial on the remaining firearm conviction, calling the police corruption and the office's withholding of evidence disgraceful chapters in its history, and in May 2021 Judge Robert Ullmann granted the new trial, ending with the gun charge thrown out¹⁵^•⁷.

Production and structure

The creative teams at Gaumont and What's Up Films began filming Ellis and his lawyers in 2017, as they prepared his defense for the anticipated fourth trial¹⁶. Director Rémy Burkel, a Paris-based filmmaker, had previously worked with Jean-Xavier de Lestrade, the executive producer known for the docuseries The Staircase¹⁷. Burkel said the original plan was a courtroom drama, and that the structure changed when prosecutors declined to pursue the fourth trial during filming¹⁸.

The eight chapters move from the murder and arrest ("Execution-Style Murder", "Usual Suspects") through the three trials ("Three Trials"), the exposure of detective corruption ("Badge of Shame"), Scapicchio's pursuit of withheld documents ("Hidden Link"), Ellis's release on bail and preparation for a fourth trial ("A Taste of Freedom"), and the election of Rachael Rollins as Suffolk County DA ("Black Irish", "Worst Case Scenario")¹⁹. The series uses animated reenactments of the crime, archival crime scene footage, and interviews with Ellis's family, jurors, journalists, and former officers²⁰^•¹¹.

Reception

Critics generally received the series favorably, with a Metacritic Metascore of 79 based on five reviews and a 100% Tomatometer on Rotten Tomatoes⁸^•⁹. Reviewers including Brian Lowry of CNN and Brian Tallerico of RogerEbert.com judged the story compelling but overlong, arguing a five or six-episode version would have been more urgent⁸. On IMDb the series holds a 7.5/10 rating from about 2,600 users²¹.

The series drew a wide audience: according to the justiceforseanellis.com website, viewers from 99 countries watched it, and in August 2021 Newsweek rated it one of the top-ten true-crime documentaries on Netflix¹⁶. Ellis, who was never able to prove his innocence in a courtroom because the fourth trial never happened, later worked for the New England Innocence Project as founder and director of its Exoneree Network¹¹^•¹⁶.

References

Topic: Encyclopedia › Arts and culture › Screen and stage › Film and television › Series and fictional screen worlds › Unscripted, reality, and web-native series › Documentary, docudrama, and lifestyle series › True crime and investigative docuseries › Premiered 2006 to 2022

Initially written Oct 3, 2026 · Reviewed: Oct 3, 2026; Oct 25, 2026 · Edited: Oct 3, 2026; Oct 25, 2026; Nov 1, 2026 · Last review: Oct 25, 2026

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