BOSTON -- A young man who helped hammer out a landmark truce among several of Boston's most violent gangs was shot to death in Roxbury Tuesday night.

NewsCenter 5's Janet Wu reported that Jamhol Norfleet, 20, was shot near his home, and his 18-year-old sister, Teah Norfleet, was wounded in the hail of bullets.

As community members attended a vigil at a neighborhood church, there was a growing fear that more violence will follow as Jamhol Norfleet's killing may have been to avenge the death of a rival gang leader.

Police said Jamhol Norfleet was the head of the H-Block gang, which brokered a truce last summer with the rival Heath Street gang.

"We were just sitting here talking. Two people across the street started shooting," Teah Norfleet said.

She would not describe the alleged assailants because she said she was terrified watching her brother die.

"He had made a complete reversal, and he was on a different path. He was a Christian, and his life had been turned around. He was working during the week. He was coming to church on Sundays," said the Rev. Miniard Culpepper, of Pleasant Hill Baptist Church.

Police, clergy and neighborhood activists joined Mayor Tom Menino to make a plea for an end to the violence.

"You all need to stop it, because you are not only hurting yourself doing these things, but you are hurting your family and people who care about you. It's got to stop, and if it doesn't stop what are you going to do? Go on and kill yourself so that there is no one left?" said India Crawford, a friend of the victim.

"My baby was scared to take a shower in her own home last night," neighbor Beth Moore said. "How is my child going to be raised in a society like this? Things need to be done. Get a shot of the schoolyard. Our kids have to grow up around here."

"Jamhol Norfleet had a past. He had problems in the past, but he worked with us for the last 14 weeks to really try to turn around his community and his friends," Boston Police Department Deputy Superintendent Darrin Greeley said.

So far, no arrests have been made. The incident marked the city's 69th murder of the year.