'Trial 4': Who was John Mulligan? Slain Boston Police detective may have been involved in crime and corruption

A few years after Mulligan's murder, his colleagues were accused of being corrupt cops who falsified search warrants to gain entry to apartments of known drug dealers
(Netflix)
(Netflix)

Netflix's new limited docuseries, 'Trial 4', is about a man who says he was wrongly convicted of murdering a police officer when he was just 19 years old. The eight-part docuseries will feature Sean Ellis as he faces his fourth trial — 25 years after he was first tried in 1995 — as he may end up going back to prison. Ellis had been previously sentenced to life and was released when new evidence came to light.

The docuseries tells the story of Sean K Ellis, who has spent 22 years in prison after being convicted in the 1993 murder of Boston police detective John Mulligan. Ellis was put on trial three times within a year, and now faces his fourth trial – which could see him back in prison for life. After his first three trials for armed robbery and first-degree murder, Ellis, aged 19 at the time, was found guilty in 1995 and sentenced to life.

His first two trials resulted in a hung jury. In 2015, Ellis was freed from jail on bail, after a judge ordered a new trial saying evidence about how the case had been handled had been withheld from the defense. Ellis, who has always maintained his innocence, is now awaiting trial number four and the prospect of life behind bars again.

Mulligan had been a Boston police detective for 17 years before his death. In the early morning of September 26, 1993, he was working a paid security detail at a Walgreens pharmacy in the Roslindale section of Boston, a detail that he worked several times a week. 

However, news reports from The Boston Globe's award-winning Spotlight team suggested that the Boston Police Department had many problems at the time. According to the docuseries, a 1991 report stated that the Boston police had serious deficiencies in solving crimes — there was inattention to detail, officers would fail to secure the scene of the crime, a lack of forensic evidence collection and heavy reliance on eyewitnesses who could be unreliable.

A few years after Mulligan's murder, his colleagues were accused of being corrupt cops who falsified search warrants to gain entry to apartments of known drug dealers and undocumented immigrants. According to the report, "Once in, they demanded money and drugs and, in exchange, either did not arrest the dealers or got their charges reduced. By not showing up for their scheduled court appearances, the officers extorted additional payments when the charges were dismissed." The three officers were Kenneth Acerra, Walter Robinson and John Brazil.

Further investigation revealed that the corrupt scheme had netted the corrupt cops hundreds of thousands of dollars and had gone on for over a decade — before, during and after the Mulligan murder and trials. In March 1997, Assistant US Attorney Ted Merritt indicted Acerra and Robinson on over 40 counts of perjury and armed robbery while Brazil was granted immunity from prosecution in exchange for informing on his colleagues.

Acerra and Robinson at first vigorously denied all charges, but a year later pleaded guilty in return for reduced sentences. It is believed that Mulligan may have been part of Acerra's and Robinson's criminal scheme. A few weeks before he was murdered, the slain detective reportedly committed an armed robbery of Boston drug dealer Robert Martin's two Commonwealth Avenue apartments with Acerra and Robinson.

'Trial 4' is now streaming on Netflix.

GET THE BIGGEST ENTERTAINMENT STORIES
STRAIGHT TO YOUR INBOX.

MORE STORIES

The fifth season of ‘The Bear’ marks the concluding chapter for the award-winning culinary drama series.
1 hour ago
The comedy series focuses on a middle-aged woman reclaiming her life after her decades-old marriage ends in divorce.
3 hours ago
‘The Drop: A Snowfall Saga’ will follow the lives of Wanda and her husband, Leon Simmons, in 1990s Los Angeles.
5 hours ago
NBC is gearing up to bring the ‘One Chicago’ franchise back for new seasons this fall
6 hours ago
‘Law & Order’ Season 26 and ‘SVU’ Season 28 will premiere later than usual this year
7 hours ago
The popular young adult series is based on the Wattpad novel of the same name, written by Ali Novak, and Season 3's release date has been set.
16 hours ago
The 'Yellowstone' spinoff features Beth Dutton and Rip Wheeler fighting to survive with their own ranch after relocating to South Texas.
18 hours ago
'Invincible' is created by 'The Walking Dead' creator Robert Kirkman and has already been renewed for Season 6, even before Season 5's release.
18 hours ago
The acclaimed Prime Video series is based on James Patterson's series of novels titled 'Alex Cross,' and now the show has been renewed for Season 3.
19 hours ago
In the Season 1 finale, Bea and Twila were cornered by KGB agent Andrei Vasiliev as the American Embassy building burned around them
1 day ago