LONG ISLAND (PIX11) --- Tyler Flach was convicted of murder Tuesday in the 2019 stabbing death of Khaseen Morris, 16, on Long Island.

Flach, 21, was also found guilty of gang assault, assault, and criminal possession of a weapon after a two-week trial in Nassau County. Morris was stabbed in the heart during a brawl near a Long Island school, prosecutors said.

At left, Tyler Flach is seen in 2019. At right, victim Khaseen Morris is seen (Left: Nassau County Police Department | Right: Family handout)

“Khaseen Morris was a bright, funny and energetic young man who, at only 16, had his entire life in front him,” Nassau `County District Attorney Ann T. Donnelly said.

The deadly fight erupted after a large group of teens got out of nearby Oceanside High School, where Morris had transferred not long before his death. Another teen, 17, suffered a broken arm and swelling to his head during the brawl, while others sustained minor injuries.

Dozens were involved in the fight, authorities said. Morris was targeted over jealousy for befriending a girl. Flach is “an associate” of the girl’s ex-boyfriend, who may have been jealous of Morris’ friendship with the girl, according to investigators.

"I'm not an automaton or a robot," Flach's lawyer said after the verdict on Tuesday. "I'm a human being with a heart and a big one at that and I'm very sad and disappointed."

Morris' family members were in court on Tuesday. They called the verdict justice fort Khaseen.

“Everybody was able to see it. You went there intentionally to do more than just cause harm. You went there intentionally to murder my brother. You targeted my brother and you murdered him and now you got what you deserved," Morris' sister said.

Flach wasn’t the only one arrested after the deadly brawl. Others were charged with second-degree gang assault.

Six of Flach’s co-defendants have pleaded guilty to various charges. Defendant Haakim Mechan is awaiting trial, prosecutors said.