ROCKVILLE, MD - DECEMBER 12: Shown is a memorial card of O'lijawon Griffin as his mother, Lunette Griffin was interviewed at her parent's home on December 12, 2013 in Rockville, Md. (Ricky Carioti/The Washington Post)

Lunette Griffin only got a quick glimpse of the designer Helly Hansen jacket her son purchased with money he earned working two jobs. But it was that jacket that ultimately cost Olijawon Griffin his life.

“It was one of the first things he bought with his paycheck,” she said of the $400 black jacket with a silver lining. “But to me, it looked like a regular jacket.”

Olijawon Griffin, 18, and his childhood friend Isaac Chase were robbed of their wallets, sneakers and other belongings in an incident 13 months ago that ended in the fatal stabbing of Griffin in the Woodley Park Metro station.

On Friday, at a hearing in D.C. Superior Court, the six young men who pleaded guilty in Griffin’s robbery and killing were sentenced. One of them, Chavez Myers, 18, of District Heights, was sentenced to 30 years in prison for first-degree felony murder; the other five, ages 17 to 20, drew sentences ranging from 15 to 19 years.

Judge Ronna L. Beck called the case a “perfect tragic illustration” of what happens when individuals carry weapons and plan to rob “innocent people,” she said. “Things go wrong and people die.”

During the sentencing hearing, Griffin, a football star at Sherwood High School in Montgomery County, was praised as a hero. Prosecutors said Griffin was fatally stabbed after he challenged a group of teens, who had earlier robbed him at gunpoint, to fight one on one instead of ganging up on his smaller friend on the platform in the Woodley Park station.

Griffin “died trying to help a friend,” said Assistant U.S. Attorney Kevin Flynn said. “He died a hero.”

In a Metro security video played during the hearing, Griffin’s last words were heard as he yelled at the teens. “C’mon on son, c’ mon. . . . Get me on the one,” he was heard saying. Seconds later, as one squared off with Griffin to fight, another teen came from behind and stabbed him once in the chest. The sound of a clink could be heard as the knife was dropped on the tile floor.

The other five participants, who pleaded guilty to a range of crimes that included armed robbery and voluntary manslaughter, were Maquan Cawthorne, 17, of Mount Rainier, sentenced to 17 years; Deon Jefferson, 18, of Landover, sentenced to 16 years; Gary Maye, 18, of Hyattsville, sentenced to 19 years; Immanuel Swann, 18, of Brentwood, sentenced to 19 years; and Greg Whittaker, 20, of Hyattsville, sentenced to 15 years.

After the sentencing, armed marshals escorted the Griffin family and their friends from the courthouse after supporters of the six men had called out threats. There were no further altercations.

Lunette Griffin, 47, sitting in the living room of her parents’ home, spoke this week about how her son was proud of the popular designer jacket he had purchased by working full time in the recycling trash unit of the National Institutes of Health and part time at a Five Guys burger restaurant. He had gotten both jobs after graduating from school that May. He had planned to attend King’s College near Philadelphia in January 2013 and had started working the jobs to pay for school and to purchase a car.

Lunette Griffin said she had worked hard for years to keep her two sons away from violence. She moved to Maryland when her sons were small. She wanted to escape her home town of Yonkers, N.Y., which she said was crowded, noisy and crime-ridden. She also decided to divorce her husband, who she said battled alcohol addiction. She fell in love with the Maryland suburbs, first moving to Silver Spring and then to Olney. She worked two or three jobs to support her sons, the last as a security guard for a federal agency.

“The irony is I moved from New York to here to keep my sons away from the violence there. I wanted to give them a better life, and I thought this was the place for that,” she said.

On the night of the killing, she said, her older son, Isiah, told his brother not to wear the jacket into the District for fear that something would happen.

But Olijawon, or Owon, as his family called him, insisted. The jacket, he told his brother, matched his tennis shoes and baseball cap.

According to prosecutors, the six teens had planned a string of robberies in the Gallery Place and Adams Morgan neighborhoods. They encountered Griffin and Chase in the 1800 block of Adams Mill Road in Adams Morgan.

Griffin, according to the teens, asked whether he could buy marijuana from them, something his mother questioned because he was subject to random drug testing at his job with NIH.

“I don’t think that’s true. I don’t know what my son did when he left out of this house and when he was with his friends. But I know he didn’t drink or do any hard drugs,” she said.

When Griffin, who stood more than 6 feet tall and weighed 235 pounds, walked into a secluded area with the teens, one pulled out a semiautomatic pistol, pointed it at him and removed his jacket.

After the robbery, Myers and his friends ran from the scene, only to later encounter Griffin, Chase and another friend in the Metro station. There, Griffin and his friends saw one of the teens wearing his designer jacket and confronted him. It was there the fight broke out and the teens attacked Chase, forcing Griffin to try to protect his friend.

“I didn’t know when we went out that I would be the only one to come home,” Chase, 19, told the judge through tears at Friday’s hearing. “They could have had that jacket. All of this over a jacket.”

Lunette Griffin said she is waiting for authorities to return her son’s jacket now that the case is closed. She says she plans to create a memorial in a room with the jacket, his football jersey, and his diploma and college acceptance letter.

Get updates on your area delivered via e-mail