MIAMI—The 15-year-old son of a veteran Canadian diplomat pleaded not guilty Monday to murder and other charges in a drug-related shootout that killed his older brother and another teenager.

Curt Obront, attorney for Marc Wabafiyebazu, entered the plea Monday on his behalf to felony first-degree murder, attempted murder and other charges. The teen is charged as an adult. Wabafiyebazu waived his appearance at the hearing, although he briefly showed up in court to meet with Obront.

“We look forward to our day in court,” Obront said.

Wabafiyebazu is the son of Roxanne Dubé, the Canadian consul general in Miami. Her other son, 17-year-old Jean Wabafiyebazu, was fatally shot in the March 30 confrontation over a marijuana deal that also left 17-year-old Joshua Wright dead.

Dubé, who was in the courtroom Monday, waved and smiled when her shackled younger son walked through.

Circuit Judge Richard Hersch set a tentative July 20 trial date, which would be extremely quick for a murder case to go before a jury.

“I recognize that might not be realistic,” Hersch said.

A hearing will be held next week on Obront’s attempt to get Marc Wabafiyebazu released on bail. In general, it is difficult for people charged with murder in Florida to get bail, but under certain circumstances it can happen.

Two other young men — Anthony Rodriguez, 19, and Johann Ruiz-Perez, 21 — also pleaded not guilty Monday in the case. They face felony murder charges based on their roles in the underlying drug deal, which involved about a kilogram of marijuana.

Police say the gunfire erupted after the Wabafiyebazu brothers tried to rob the drug dealers, with Jean Wabafiyebazu and Wright fatally shooting each other. Marc Wabafiyebazu allegedly shot at Rodriguez, who had been wounded by Jean Wabafiyebazu, according to an indictment.

Under Florida law, a person can be charged with murder for participating in another crime, such as armed robbery, that leads to someone’s slaying.