Thompson's prosecution of Peter Liang, a 27-year old Asian-American rookie cop, in what jurors would later find to be the reckless criminal manslaughter of an innocent black man, Akai Gurley, cast the intrepid former federal prosecutor in the roles of hero and villain in Brooklyn's cauldron of identity politics.
At first, Thompson was widely praised in the black community for demonstrating the courage to indict a police officer for what that community clearly believed to be yet another unjustifiable killing of an innocent black civilian.
The accolades in the black community were later followed by harsh criticism from two of New York City's powerful police unions who claimed that Thompson was "criminalizing" a tragic accident and that this would have a "chilling" effect on policing in New York.
Thousands of Asian-Americans from Brooklyn and other parts of the country also gathered to demonstrate against the DA, asserting that the indictment reflected a bias against Asian-Americans who often own and operate stores in poor, largely black urban neighborhoods.
The criticism from the cops bore a particularly harsh sting for Thompson since his own mother was one of NYPD's early female patrol officers. She remained "on the job" for over 21 years.
He remembers her coming back after her shift to his own public housing project in the Bronx dressed in her police uniform in the high-crime 1970s. Thompson spent a lot of time at police precincts with his mother, and he respects cops but says they too must be held "accountable" before the law and the community they serve.
Mindful of the controversies in recent police shooting cases, Thompson quickly ordered a comprehensive investigation of the Gurley shooting. Attorneys and investigators from his office determined that Officer Liang had shot Gurley in the pitch black stairwell of one of Brooklyn's most dangerous public housing projects.
Thompson's prosecutors concluded that though the shooting was accidental, it rose to the level of reckless criminal conduct. The young, fearful officer had drawn his .9mm Glock pistol and apparently had his finger on the trigger
in violation of NYPD training rules that require a specific threat or provocation before an officer can place his finger on the trigger.
As frightening as it may have felt to the inexperienced Liang, darkness in the eighth floor stairwell of a public housing project does not qualify as an explicit threat.
Strongly disagreeing, Lt. Robert Rahn, a former housing cop and now private investigator who did "vertical patrols" on every tour in the1970s Bronx with gun drawn, told me "... walking those pitch black halls was the scariest thing I have ever done ... you can be damn sure my gun was drawn."
He also cites the death of Officer Anthony McLean
killed in a project stairwell, asserting that such deaths weigh heavily
on the minds of police officers involved in vertical patrols.
When "startled" by an unexpected noise, Liang pulled the trigger of his gun. He exerted 11.5 pounds of finger pull, causing a bullet to ricochet off a concrete slab into the heart of the innocent father of a 3-year-old girl on the stairwell below. His only mistake had been to enter a stairwell while it was being patrolled by two NYPD officers sworn to protect him.
Liang's conviction may have been sealed when the judge at the prosecutor's request, permitted the jurors to each pick up Liang's now unloaded Glock and pull the trigger.
This grim demonstration of "pull weight" was undoubtedly unforgettable. How much pressure was required? For comparison purposes, a medium-sized bowling ball or a 3-month-old baby often weighs around 10 pounds.
It undoubtedly left an uncharged thought in the minds of jurors: Was the trigger pull intentional?
Brooklyn prosecutors also believed that that Liang's recklessness with the weapon was compounded by yet another reckless criminal act.
Instead of immediately calling for an ambulance and administering CPR to help save the dying 28-year-old Gurley, Liang and his partner
were alleged to have argued
about who should administer CPR and whether the shell-shocked Liang would get fired from his job as a police officer. He had graduated from the police academy less than 12 months earlier.
In the meantime, Gurley lay dying on the bloody project floor while a friend from the building, Melissa Butler, administered CPR under the telephone guidance of a 911 operator who was called on a neighbor's phone.
Sadly for Gurley and his daughter Makaila, all efforts to save him proved futile. His visit to Butler's apartment at the "Pink Houses" to have his hair braided in preparation for a visit to his mother in Florida with his young daughter would be his last act on this Earth.
When confronted with this tragic set of facts, Thompson felt that he had no choice but to seek an indictment before the grand jury for reckless manslaughter and official misconduct. The grand jury concurred, voting for charges that could have exposed Liang to a maximum of 15 years in prison.
Then the DA did something even more extraordinary than displaying the courage to indict a cop in an accidental but "reckless" shooting.
He asked that the court to extend mercy to the young officer, noting in a moving letter to the trial judge, Denny Chu, that the case had "mitigating circumstances" including the fact that the defendant never intended to "... kill or even injure Mr. Gurley." He "... chose to become a police officer, and to put his life on the line ... to protect the public."
During a public appearance announcing his no jail
recommendation, Thompson stated that the case was "about justice and not revenge..." and that the young officer, who had already lost his job, would pose "no threat to public safety" if given a sentence of home confinement, community service and probation.
The unusual plea for leniency by the tough prosecutor stirred a wave of opposition and criticism in the previously supportive black community. In taking this brave stance, Thompson risked forfeiting the support of the one group of constituents who had been firmly in his corner.
After the hard-won conviction, the moment of sentencing arrived on Tuesday when the case was called before Chu. The judge had previously refused to grant a mistrial based on an allegation of juror misconduct or to set the verdict aside on defense motion "as against the weight of the evidence."
Thompson's no-jail recommendation was largely followed
by the the judge, who reduced the conviction from manslaughter to criminally negligent homicide. He did increase the amount of community service to 800 hours from Thompson's recommended 500. The judge also ordered five years of probation but no jail.
Without the DA's strong recommendation, Liang may well have been sentenced to prison.
The defense will appeal, and the critics will continue to attack Thompson for having the audacity to indict a cop or alternatively by claiming the DA sold out by recommending leniency. But a good DA has to do what he thinks is right. In many respects, he is the moral compass of the community, and my guess is Thompson remains comfortable in his shoes.
Brooklyn's first African-American district attorney demonstrated courage and a toughness tempered by mercy in his handling of this tragic case.
Thompson sent a message to the community that the much-criticized criminal justice system really can find the path to police "accountability" but that sometimes the path to justice also requires mercy.
Ken Thompson's handling of this difficult case has also set an example for the rest of the country to consider in future police/civilian shooting cases.