Testimony focused on a prison tip allegedly identifying the suspect, cellphone data and the defendant’s statements as the first-degree murder trial of Dion Thompson continued on July 29 before Baltimore City Circuit Court Judge Cynthia H. Jones.
Thompson, 27, is represented by defense attorney Staci Pipkin. The defendant is charged with first-degree murder, firearm use in a felony violent crime, attempted first-degree murder and other related offenses in connection with the Nov. 4, 2017, fatal shooting of off-duty Washington, D.C., Police Department Sgt. Tony Mason Jr.
According to charging documents, Mason was sitting in a vehicle with his girlfriend on the 2800 block of Elgin Avenue shortly after midnight when another vehicle pulled alongside them. One of the occupants allegedly shouted before multiple shots were fired, killing Mason and injuring his girlfriend.
The state’s first witness was an administrative specialist who testified that a longtime friend, who was incarcerated, told her his cellmate, alleged to be Thompson, had discussed committing a murder.
The witness said she contacted the Baltimore Police Department (BPD)and was directed to submit the information through the Crime Stoppers program. A detective later contacted her.
According to the witness, her friend sounded upset and said he felt he would be as guilty as the person responsible if he did not report what he knew. She testified that neither she nor her friend sought reward money.
The witness said she had no connection to Baltimore and did not know Thompson. During cross-examination, she testified that she spoke with her friend about the information five or six times and initially provided only limited details.
The state next called an FBI agent who said federal authorities assisted with the investigation into Mason’s death.
The agent testified that investigators extracted data from Mason’s cellphone, but the search did not produce any leads. She also obtained tower transmission records showing cellphone activity in the area on the night of the shooting.
The agent said she interviewed the incarcerated informant in January 2023. The interview was not recorded because investigators did not have permission. According to the agent, investigators took detailed notes and did not provide the informant with information that could influence his account. She said investigators later corroborated portions of what he told them.
The informant provided information about a social media account, which led investigators to obtain a search warrant and identify a phone number connected to the account. The agent testified that the number appeared in tower data from the area around the time of Mason’s killing.
The agent also testified about interviewing Thompson. She said Thompson was advised of his rights, signed a form agreeing to speak and initially appeared calm.
Investigators showed Thompson photographs of relatives and known associates before discussing Mason and the homicide. The agent said Thompson’s demeanor changed when the conversation turned to details of the crime, noting that he began sweating and breathing heavily.
According to the agent’s notes, Thompson asked, “Where’s the gun? I want to know.” She testified that investigators had not mentioned a gun before Thompson raised the subject.
After Thompson reviewed his charging documents, the agent said he stated that he knew who had provided the information because he had been incarcerated with the person.
The agent also testified that Thompson recalled receiving a call on the night of the shooting in which someone said a person had been “spent.” Investigators were unable to corroborate the alleged call.
No firearm was recovered in the case.
During cross-examination, Pipkin questioned whether investigators could determine how many people fired shots. The agent said they could not say for certain whether there were two shooters.
The agent testified that a witness reported seeing a muzzle flash from the passenger side of a vehicle and provided a limited description of the shooter.
Pipkin also questioned why investigators interviewed Thompson in prison, where the interview could not be recorded, instead of transferring him to Baltimore for a recorded interview.
The agent acknowledged that investigators knew before the interview that Thompson would be charged with murder but did not immediately tell him.
Additional testimony is expected as the trial continues.
