A 21-year-old Canton man was convicted of murder for the fatal shooting in Dorchester of 15-year-old Curtis Ashford Jr. in the summer of 2022.

“Losing someone so young to violence is a blow to the entire city. Every person who cares about the health of our neighborhoods and the safety of our young people — and that should be all of us — should be shocked, saddened and motivated to make things better,” Suffolk District Attorney Kevin Hayden said. “But nowhere is Curtis’s loss felt more profoundly than by his family and friends, and they will always have our sympathy and our support.”

A Suffolk Superior Court jury on Monday convicted Zontre Mack of the first-degree murder of Ashford. Judge Mary Ames scheduled sentencing for Oct. 23 at 9:30 a.m.

A co-conspirator, Dominick Gavin, 27, of Boston, pleaded guilty in August to being an accessory after the fact, for which he was sentenced to three to four years in prison.

Ashford, who had promised his mother he would be home by 8 p.m., was playing basketball at a playground in the Erie-Ellington neighborhood when he was gunned down around 7:30 p.m. on July 27, 2022. He would be pronounced dead at Boston Medical Center within the hour.

Prosecutors say Mack drove to the area of Ellington Street that evening.

“It was a hot July day and he was still wearing a full-length black hoodie and the hoodie was up over his head and he walked a short distance to Ellington Street,” prosecutor Julie Higgins said at Mack’s arraignment that November, where he “then fired 15 rounds at a group of individuals that were standing around a parked white Range Rover.”

Ashford dropped his bike and tried to flee the area on foot with the others but was shot in the back, Higgins said.

Mack was 19 at the time and had no prior adult criminal record. He did, however, have a juvenile record that included 27 entries, according to previous Herald reporting. Although most of the cases had been dismissed, notable entries included charges of assault and battery with a dangerous weapon — a shod foot — against a person over 60 in 2019 and a charge of assault and battery on a police officer and resisting arrest in 2020.