The Supreme Judicial Court on Thursday upheld Shaquille Brown's conviction for murdering Christopher Austin on Ashmont Street in 2017.

The ruling means Brown will spend the rest of his life in prison.

The state's highest court acknowledged arguments from Brown's attorney that prosecutors said some things they probably shouldn't have to convince a grand jury to indict Brown and to then convince a Suffolk Superior Court jury to convict him, but ruled that overall, the mistakes were minor and did not unfairly prejudice Brown's case.

The court also concluded that even though two people who saw a man matching Brown's description fleeing from the scene did not get a good look at his face, and that police were unable to link the guns and ammunition found in the room in Brown's mother's Mattapan house where he was staying to the murder, there was still enough evidence to convict him - including the distinctive baggy pants he wore and the fact that the man seen going up to Austin and then hurrying away had a chipped tooth. A store security camera also produced video evidence tying him to the scene.

According to the court's summary, Austin was walking down Ashmont Street to the Red Line to get to his job at Logan Airport on June 28, 2017 when he went into a store on the way to buy something.

"When he arrived, two men were sitting in a blue Honda Accord that was parked in front of the store. One of the men, later identified as the defendant, got out on the passenger's side and stood next to the Accord while the victim completed his purchase inside. As the victim left the store and walked down Ashmont Street, the defendant bent down toward the Accord before getting back into the vehicle and closing the door. Several minutes later, as the victim continued walking east on Ashmont Street, the Accord pulled away from the curb and traveled in the same direction down the one-way street."

The car stopped, the passenger got out, went up to Austin, appeared to have a conversation with him and then shot him in the eye, killing him.

The driver of the car was initially charged with Austin's murder as well, but prosecutors dismissed the case against him for lack of evidence that he had anything to do with the murder.

The court rejected arguments from Brown's lawyer that prosecutors failed to show the premeditation required for a first-degree murder conviction:

"In this case, there was lay and medical evidence that the victim had been shot at close range through the eye. Emergency medical technicians attempting to treat the victim at the scene noted signs of stippling on his face, indicating that the shot had been fired from only a few feet away. Minutes before he heard the gunshot, a witness saw the victim standing and talking to a man whose physical characteristics matched the defendant's, and wearing clothes that appeared to match clothing the defendant had been wearing less than ten minutes earlier. The two men appeared to be talking calmly and in a friendly manner. No one else appeared to be outside on either side of the street.

"From this evidence, the jury reasonably could have inferred that the shooter, who had been talking to the victim as they stood near each other, decided to kill the victim, pulled out a gun, and shot him in the face at point-blank range. This, in turn, was sufficient for the jury to have found that the shooter acted with deliberate intent to kill the victim; any reasonable person would know that shooting someone in the head at close range almost certainly would result in death, and there was no evidence of any kind of sudden combat or self-defense."