Calgary police say three 15-year-old boys have been arrested in connection with the killing of 16-year-old Carter Spivak-Villeneuve in August.

Officials say one of the boys was arrested on the Muskowekan First Nation in Saskatchewan on Nov. 4 while another was arrested Nov. 12 in Calgary.

Both of those boys have been charged first-degree murder.

A third boy was arrested and at a media update Thursday. Staff Sgt. Sean Gregson of the city’s Homicide Unit confirmed that he has been charged with one count of first-degree murder.

He’s scheduled to appear in court Monday.

Calgary police were called to a greenspace in the 300 block of Abbeydale Drive N.E. at 1:20 a.m. on Aug. 1.

On arrival, they found the body of another male youth, later identified as Spivak-Villeneuve.

Officials say the youths arrested in the case were known to the victim and had arranged to meet with him that night.

“Carter’s death is alleged to be the result of an ongoing dispute,” police said in a news release.

Gregson called Spivak-Villeneuve’s death “devastating.”

“The loss of Carter is a devastating reminder of how seemingly insignificant conflict between youth can escalate with irreversible consequences. Carter’s death was senseless and the lives of everyone involved have now been forever changed,” he said.

The youths cannot be named under the provisions of the Youth Criminal Justice Act.

Police say the investigation is still ongoing.

Anyone with information is asked to contact police.