It was Easter weekend nearly two years ago when Maurice Bellamy decided a youth he encountered on a Metro station platform was staring at him. Bellamy opened fire, killing the 15-year-old boy who had been headed to a haircut for church services the next morning.

Months before that, Bellamy had fatally shot another unarmed stranger. The victim was an off-duty U.S. Secret Service officer who was sitting in a car waiting for a friend.

On Friday, after more than a week of often emotional and graphic testimony from eyewitnesses to the killings, a D.C. Superior Court jury convicted Bellamy, now 19, of both murders. He faces a maximum of two life-prison terms when he is sentenced July 20.

On March 26, 2016, Bellamy was at the Deanwood Metro station when he approached Davonte Washington, 15, as the boy was waiting for a train with his mother and younger sisters. Bellamy, then 17, accused the younger teen of “mugging” at him, or staring at him in a threatening manner.

In a scene captured on video surveillance, Davonte stepped between his family and Bellamy and put his hands up. Davonte’s mother, Rashida Washington, testified that her son seemed confused. Bellamy pulled his ­.38-caliber pistol from his pocket and shot Davonte twice before running out of the station.

During the trial, Washington tearfully told jurors how she chased the shooter through the Metro station before returning to the platform to her dying son and her daughters, who were kneeling beside him.

Three months earlier, on Dec. 15, 2015, Bellamy used the same gun when he and two friends tried to hold up Arthur “A.J.” Baldwin, the off-duty officer, as he sat behind the driver’s seat of a rental car. Prosecutors said the trio mistakenly thought Baldwin was a drug dealer and had set out to rob him.

According to testimony, Bellamy grabbed the handle of the driver’s side door and ordered Baldwin to turn over money. As Baldwin tried to push his way out of the car, Bellamy fired multiple shots. Two witnesses who were at the scene of the shooting, one of whom pleaded guilty to second-degree murder, outlined Bellamy’s role in the shooting. Authorities also found Bellamy’s DNA on the car door.

Prosecutors called both murders “senseless.” In her closing arguments, veteran homicide prosecutor Deborah Sines urged the jury to disregard Bellamy’s youthful age at the time of the killings and find him guilty of first-degree, premeditated murder.

“This wasn’t an accident. This wasn’t self-defense. This was on purpose. Under our laws, if you kill someone when you are 17, you are held responsible, just as if you are a man,” Sines argued.

Bellamy’s attorneys, Steven Kiersh and Kevin McCants, repeatedly argued that their client did not plan to kill Davonte and rejected the premeditation charge. The attorneys also contended that one of Bellamy’s friends, who was with him during the attempted robbery, was the one who fired.

The jury ultimately rejected the attorneys’ assertions and found Bellamy guilty of two counts of first-degree murder while armed and robbery.

Kiersh also argued that Bellamy was not mentally responsible for his actions.

According to a Post investigation a month after his arrest, Bellamy had struggled with his temper since he was in grade school. During the trial, Bellamy’s mother, Keisha Shelton, testified that she noticed her son began showing impulse control issues when he was in the second grade.

“He would do things and not think about the consequences,” she told the jury. A doctor prescribed a medication to help him control his temper and reduce his anxiety. His mother enrolled Bellamy in a private school in Maryland, teachers were able to focus Bellamy’s energy into his classwork, and he was the speaker at his eighth-grade graduation.

But in 2013, Bellamy’s family moved to Southeast Washington. Shelton said D.C. school officials initially told her that Bellamy could remain at his Maryland school, even when she moved to the city, but that didn’t happen. For five weeks, Bellamy, then 15, drifted while his mother tried to get the school system to enroll him at Ballou High School, which was within walking distance of the family’s new home. When Bellamy finally started classes, his absences, bursts of anger and failing grades quickly piled up. During his freshman year at Ballou, Bellamy was arrested on a charge of simple assault for threatening a school employee. He eventually dropped out of school.

During cross examination, Sines asked Shelton if she blamed the D.C. school system for her son’s troubles.

“They definitely played a part,” Shelton told the prosecutor.

But Sines later rejected Shelton’s assertion. “The D.C. public school system did not kill this 15-year-old child. Mr. Bellamy did,” she said holding up a ­poster-sized picture of Davonte.

The Bellamy case marked the final murder trial for the 65-year-old Sines, who has been a homicide prosecutor within the U.S. Attorney’s office since 1985 and is retiring in April. Sines has tried some of the city’s most horrific murders, including the 2009 murder trial of Banita Jacks, the Southeast Washington woman convicted of killing her four daughters and living with their decomposing bodies for months.

Outside the courtroom, Sines hugged the victims’ families.

“This doesn’t bring them back. This will hurt always,” she said as Davonte’s mother and Baldwin’s wife both hugged her.