A daughter of Sen. Robert F. Kennedy and a son of Martin Luther King Jr. helped launch a campaign against capital punishment on Friday, saying the death penalty will not bring their slain fathers back to life.

Society should put some killers in jail "and leave them there forever. But while we're at it, dismantle the electric chair, the gas chamber. They won't bring back my father, they'll only take someone else's father," said M. Kerry Kennedy of Boston, who was 8 when her father was killed in 1968.Other speakers during a meeting at the Martin Luther King Jr. Center for Nonviolent Social Change urged religious leaders to become more active in mobilizing their congregations against the death penalty.

The campaign, called "Lighting the Torch of Conscience," is aimed at getting the religious community to confront the capital punishment issue. It will culminate in June 1990 with a 330-mile pilgrimage from Starke, Fla., where Florida's electric chair is located, to Atlanta.

Camille Bell, an Atlanta woman whose son Yusef, 9, was murdered in 1979, also spoke against capital punishment. Yusef Bell was one of more than 20 young black Atlantans whose deaths were attributed by police to Wayne Williams, currently serving two life prison terms for two of the killings.

"I know the pain I felt when Yusef died," Bell told the gathering of about 100. "No other mother should have to feel that pain."

Martin Luther King III, a son of the slain civil rights leader, said the execution of King assassin James Earl Ray "would not bring my father back."

"If we believe in an eye for an eye and a tooth for a tooth, most of us would be without eyes and without teeth," he said.

Friday's session opened with Delbert Tibbs, a former Florida death row inmate, carrying a lighted torch from King's tomb into an auditorium of the King center.