Patricia Rosier and Darius Stanton, along with other panelists, hold a public forum on youth violence in Capital Heights, Md., on Tuesday. (Linda Davidson/The Washington Post)

Marcus Williams had more than 16 friends who were fatally shot, enough to fill a classroom. Some were killed in the most innocent of circumstances — a pair of shoes that drew unwanted attention, something said to somebody, being in the wrong place at the wrong time, just walking to school.

“My friend Christopher was coming off the train, and people outside started shooting and he got hit,” Williams, 17, recalled. “Another friend was killed. He was just about to graduate high school. The one that sticks with me is my friend Marckel.”

Marckel Ross, 18, who was a senior at Central High School in Capitol Heights, was one of six teenagers killed in Prince George’s County in a six-month period during the last school year. None of the shootings happened in a school.

Ross was shot walking to school. “He didn’t even get to see 19,” Williams a crowd gathered Tuesday night in Central High’s auditorium at a forum on youth violence organized by Men Aiming Higher, a mentoring organization. “I know life is short. Anything can happen any day. . . . I try to put my mark on the world, and I always pray.”

Darryl Barnes, president of the mentoring group, told the crowd that it is urgent to find solutions to violence against youth. “Look at what happened here at Central High School. Look at what happened at Suitland High School, where a child was shot for Timberlands,” Barnes said. “We have to stop the violence.”

The Rev. Jeffery O. Thames speaks Tuesday at a forum on youth violence in Capitol Heights, Md. (Linda Davidson/The Washington Post)

The killings that jolted the county last year just as a new school year was beginning seemed to make little sense. A community was left struggling over how to keep teenagers safe when there is no pattern to the crime, no rule to follow, no instruction that could offer security.

Ross was fatally shot September 2012 as he walked to school. Police believe that he might have been a robbery target. Days earlier, Amber Stanley, a senior at Charles H. Flowers High School, was killed in her home in Kettering. In December, Eliezer Benjamin Reyes, 14, a student at Foundation School, an alternative school in Largo, was killed in a drive-by shooting while walking with two acquaintances. Marcus Jones, a sophomore at Friendly High School, was shot in January shortly after leaving a party in Fort Washington.

In February, Aaron Kidd, 18, a freshman at Suitland High School, was killed while hanging out with friends outside an apartment complex, and Charles Walker Jr., 15, also a freshman at Suitland, was fatally shot while walking to school. Police said Walker was robbed by assailants who wanted the Timberland boots he was carrying in a shopping bag.

And if those crimes hadn’t done enough to shake the resolve of parents, many then had to explain to their children the acquittal of George Zimmerman, who was charged in the slaying of Trayvon Martin, an unarmed 17-year-old.

In the quiet auditorium at Central High, more than 100 parents, community activists, and county and state officials sought answers to how to keep more children from dying violently.

Despite the violence and the challenges that youths face, most are thriving, said Darius A. Stanton, the panel’s moderator. “The focus here is not to bash anyone. We want to know how we can impact young people so we don’t lose more lives.”

“We want to teach young people how not to put themselves in a position that Trayvon Martin was in,” Stanton said. The teenager was killed while on his way from a store to his father’s home in a gated Florida community. Zimmerman, a neighborhood watch volunteer, told authorities that he thought the teenager looked suspicious.

“This is a serious topic we need to discuss,” said Bob Ross, president of the Prince George’s County chapter of the NAACP. “Trayvon Martin was going home with Skittles and tea. No one has the right to take someone’s life. In Prince George’s, we have to look at the same issues.”

Audience members lined up at microphones. One mother asked: “What do I tell my son? How does he stay safe? Do I tell him he can’t walk to the store to buy candy?”

The Rev. Jeff Thames Sr., founder of the advocacy organization Hope Restored, said parents need to tell youths to leave situations that appear threatening. Tell them, “ ‘When you see something strange, run away from it,’ ” Thames said. “I spend a lot of time in nature. When a hawk lands in a tree, birds begin to sing and chirp, and everything in the forest comes to a halt, indicating there are predators out there waiting for them to make a mistake.”

Dorothy C. Elliott asked that the county reopen the case involving her 24-year-old son who was fatally shot in 1993 while handcuffed in a police cruiser. “I feel like I failed my son,” she said. “He was just beginning to live life.”

After three hours, the forum ended, and Marcus Williams, the 17-year-old who had told the panel how violence has affected him, prepared to walk home. He stood up straight and swung his backpack on. The street from the school to the main road is not so bad, he said. Central Avenue is fine, too, until he reaches a patch where darkness falls and there are no streetlights.

For these few blocks bordered by woods, “I keep my head on swivel,” Williams said. “People get jumped, and there are crackheads.”

There, he quickens his pace, knowing that if he can reach the next streetlight, he will be safe.