MINEOLA, NY (PIX11) — A Long Island man was sentenced to 25 years to life behind bars on Tuesday for stabbing a teen to death, officials said. 

Tyler Flach, 22, was convicted of murder charges in the 2019 Oceanside stabbing death of Khaseen Morris, 16. Morris was killed by a stab wound in the chest during a brawl.

Keyanna Morris, the teenage victim’s sister, previously said she would stand strong and fight for her brother. She described Flach as a monster who deserves to stay behind bars.

“He knew what he went to do. He chose to do what he did. He chose to get in that car. He chose to bring a knife. He chose to stab my brother,” she said at court on Tuesday. “All of those were his decisions, thought through decisions. So I refuse to entertain any sob stories from Tyler”

Before the deadly fight, Flach was angry that Morris had walked a girl home, Nassau County District Attorney Anne Donnelly said. He organized a group and went to a strip mall, intending to attack Morris. 

“Tyler Flach stabbed Morris in the chest and took the young man’s life,” Donnelly said. “This was an incredibly senseless murder and I thank our prosecutors, the Nassau County Police Department detectives and the jurors who sat on this trial, for carefully reviewing the evidence.”

Morris was described as friendly and intelligent. He’d just transferred to Oceanside High School and had only been there for around 10 days before the deadly attack, officials said. Morris died on Sept. 16, 2019. 

Flach was convicted or murder, gang assault and weapons possession, prosecutors said. He was also found guilty of assault in the third degree for breaking the arm of another teen. His attorney said Flach intends to appeal.

“Tyler’s many things, he’s not a murderer. He didn’t mean to kill anyone,” attorney Kevin Dunshee said.

Co-defendant Haakim Mechan was sentenced on Feb. 23 to three years in prison with three years of post-release supervision after pleading guilty to attempted gang assault in the second degree.