DELTA, Pa. (Reuters) - After her son shot five Amish schoolgirls to death in 2006, Terri Roberts could have gone into hiding to nurse her pain, like many parents of mass murderers have in the past.

Instead, she broke with convention. Drawing inspiration from the Amish who were so quick to forgive her son, Roberts, 62, has embraced the victims' families in return and now publicly tells her story about the power of forgiveness.

On Oct. 2, 2006, Charles Roberts, 32, took 10 Amish girls hostage in their one-room schoolhouse in rural Pennsylvania, lined them up and shot them in the head. He then killed himself. Five girls died. Five survived.

Along with that, Terri Roberts herself became a victim, forced to confront life knowing that her son had committed such an atrocity.

"I remember falling to the ground and writhing," she said, recalling the day of the shooting.

When the Amish forgave her son, it allowed Roberts, who is not Amish, to forgive him as well.

The response to mass murder in America has become almost routine. A gunman goes on a rampage, killing defenseless civilians. Families of the victims grieve. Investigators gather evidence. The media descend on the scene until the narrative moves elsewhere.

The shooter's parents, who face blame in the public eye for having produced a killer, typically issue a brief statement and then try to find solace in anonymity.

In Newtown, Connecticut, where the anniversary of last year's Dec. 14 school massacre is approaching, the shooter's father issued a written statement expressing grief. After last year's movie theater shooting in Aurora, Colorado, an attorney for the gunman's family read a statement. In September, the mother of the Washington Navy Yard shooter recorded an audio message. Subsequently they have all remained in the background.

After nine months in hiding, Roberts went public. She has traveled to eight states so far, with plans to journey abroad as far as Japan and Peru, to offer her message to churches and other groups who invite her.

"Absolutely nothing about this has felt wrong," Roberts told Reuters in an interview. "I feel compelled to share this message."

It all started with the Amish. Famously reclusive, they are traditionalist Christians who shun modern technology - preferring the horse and buggy over cars, for example - and live much as their ancestors did when they migrated to rural Pennsylvania in the 18th Century.

Many of them attended the funeral for Charles Roberts, one day after they had buried their own girls, ages 7 to 13.

"I never even thought about going to the girls' funerals, and yet the Amish came to Charlie's," Roberts said on Sunday, addressing more than 200 people who came to hear her at the New Covenant Community Church, in Delta, Pennsylvania, about 25 miles (40 km) from the site of the shooting in Bart Township.

"The first two parents to meet our family were parents who had lost two daughters," Roberts said. She then addressed a question to the stunned and silent congregation. "Who here has anything inside that they cannot forgive or will not forgive?"

A FATHER FORGIVES

Forgiveness came more slowly to one Amish man whose 12-year-old daughter died in the shooting. He needed more time, even after he decided to forgive, he could not yet feel it in his heart.

He still feels "anger and disturbing thoughts" sometimes, said the father, who spoke to Reuters on the condition of anonymity out of respect for other Amish families who are not comfortable with media attention.

Upon hearing the reason behind Charles Roberts' violent act - he was distraught over the death of his infant daughter nine years earlier - the Amish man found it easier to forgive.

"The journey of grief and forgiveness is much easier with faith in God," he said.

Roberts has maintained a relationship with her son's Amish victims' families in the seven years since the attack. She spends every Thursday with the most badly wounded of the five survivors. The wheelchair-bound girl needs a feeding tube.

One of Roberts' three remaining sons, Zachary, is making a documentary called "Hope" about his mother's journey. He is trying to raise funds online in order to complete his work.

A reporter asked Roberts if her message might help the people of Newtown, Connecticut, as they approach the first anniversary on Dec. 14 of the attack at Sandy Hook Elementary School, where a 20-year-old gunman shot dead six adults and 20 children ages 6 and 7 before killing himself.

"Oh, if they want to hear it, they can hear it," Roberts told Reuters, her voice breaking and eyes moistening. "I would just never force myself on them. I know what they are going through. So many unanswered questions."

(Reporting by Daniel Trotta; editing by Gunna Dickson)