Baltimore prosecutors have announced the arrest of Dion Thompson for the 2017 murder of off-duty Washington, D.C. police sergeant Tony Anthony Mason Jr. Thompson, who was 18 at the time, allegedly shot Sgt. Mason to death while he was sitting in a parked car with a woman he was dating. The case remained unresolved until a tip was received in early 2023, leading authorities to Thompson. He is currently serving time in a federal prison on unrelated charges. Thompson’s charging documents do not provide a clear motive but are based on the account of someone who knew Thompson and claimed he admitted to the shooting out of paranoia.
The witness stated that Thompson shot at the parked car because he didn’t recognize the occupants and assumed they were there to rob him or retaliate for his criminal activities. Thompson later learned from the news that the victim was a police officer and allegedly drove to Philadelphia to get rid of the vehicle he was driving. Thompson’s charging documents mention two other people involved in the shooting, one of whom died in a car crash. No one else has been charged in the case. Mason, a 17-year veteran of Washington’s Metropolitan Police Department, was unarmed and not wearing anything to identify himself as an officer during the attack.
Detectives found no signs of criminal or gang activity in background checks on Mason and his companion. Metropolitan Police Department Chief Pamela Smith expressed the hope that Thompson’s arrest would bring some closure to those affected by Mason’s death. Baltimore State’s Attorney Ivan Bates stated that this case would be the first prosecution handled by the office’s new cold case unit. Thompson’s attorney did not respond to requests for comment. Prosecutors said that Thompson shot at the car out of paranoia, believing the occupants were there to rob or retaliate against him for his previous criminal activities.
Thompson disposed of the vehicle after learning from the news that the victim was a police officer. The charging documents also mention two other individuals involved in the shooting, one of whom was killed in a car accident. Mason’s background check revealed no criminal or gang activity, and he was not equipped to identify himself as a law enforcement officer during the attack. Chief Smith expressed relief that Thompson was being brought to justice for Mason’s murder, which had remained unsolved for many years. Bates stated that the case marks the first prosecution carried out by the office’s new cold case unit.
The witness who provided information on Thompson’s involvement in the shooting did not provide a clear motive for the crime. Thompson is currently incarcerated on unrelated charges in a federal prison. His attorney has not released a statement regarding his client’s arrest in connection with Mason’s murder. The case was revitalized by a tip received in early 2023 that pointed authorities towards Thompson. Thompson was 18 years old at the time of Mason’s murder and allegedly acted out of paranoia when he shot at the parked car containing Mason and his companion.
