A dedicated police officer, father, and son, Tony Anthony Mason Jr. was known for a commitment to his community that went far beyond the badge. A 17-year veteran of Washington, D.C.'s Metropolitan Police Department, the 40-year-old Black man was remembered as the kind of officer who believed in extending a helping hand, especially to young men in need of guidance. His life, however, was cut short in a senseless act of violence. He is survived by his father, two daughters, two sons, and a sister.
In the pre-dawn hours of November 4, 2017, Mason was off-duty, unarmed, and not in uniform. He had spent the evening on a date with a woman he had been seeing for about a month. After a trip to Walmart and a liquor store, they were sitting and talking in his parked black Nissan Versa around 12:45 a.m. in the 2800 block of Elgin Avenue in West Baltimore. Suddenly, another vehicle pulled alongside them. Someone inside yelled out before opening fire, unleashing a barrage of bullets into Mason's car. Mason was struck multiple times and was rushed to the University of Maryland Shock Trauma Center, where he was pronounced dead. The woman with him was shot in the leg but survived her injuries. Investigators from the Baltimore Police Department recovered 16 shell casings from two different 9mm handguns at the scene.
For years, the investigation into Mason's murder yielded no answers, leaving his family and colleagues with a painful mystery. Detectives initially explored the possibility of a domestic dispute but found no evidence to support the theory. Extensive background checks on both Mason and his companion showed no connections to any criminal activity. The case went cold for nearly six years, a period of agonizing uncertainty for all who knew and loved Sergeant Mason. The city where he lived and was killed, Baltimore, recorded over 300 homicides in 2017.
A major breakthrough finally came in early 2023 when a crucial tip was submitted to Metro Crime Stoppers. This new information pointed investigators toward a man named Dion Thompson, who was just 18 at the time of the shooting. The tip came from a witness who stated that Thompson had admitted to the killing. According to charging documents, Thompson was the leader of a local drug gang called "The Slickest Ones" and had become paranoid that a rival crew was planning to rob or retaliate against him for robberies he had committed. Tragically, he mistook Mason's parked car for that of his enemies. After the shooting, Thompson allegedly told his brother he "got one tonight," and to "watch the news." He only learned the identity of his victim after seeing news reports.
In April 2024, Baltimore authorities announced murder charges against Dion Thompson, who was already serving a sentence in a federal prison in New Jersey for unrelated drug and gun convictions. The prosecution was the first for the Baltimore City State's Attorney's Office's new Cold Case Homicide Unit. The investigation was a collaborative effort involving the Baltimore Police Department, the FBI, and the ATF. "For nearly a decade, Sergeant Mason's death has weighed heavily on his family, our Department, and the community he served," said D.C. Metro Police Interim Chief Jeffery W. Carroll. "We hope this verdict provides some measure of peace for everyone who continues to feel the weight of his loss."
In July 2026, a Baltimore jury found Dion Thompson guilty of first-degree murder, conspiracy to commit murder, and the attempted second-degree murder of the woman in the car with Mason. During the sentencing in August 2026, the court heard a victim-impact statement from one of Mason's daughters, who was very young when he died and spoke of the pain of growing up without her father. The surviving victim also addressed the court, describing the nine years of trauma she endured. Thompson was sentenced to two life sentences plus 33 years in prison. "While no amount of time can restore the years Sgt. Mason's family have lost, today's sentence...ensures that Defendant Dion Thompson will spend the rest of his days being held accountable for the devastating choices he made," prosecutors said in a statement. The case is now considered solved and closed.
