The parents of Ana Márquez-Greene, the six-year-old former Winnipeg girl who was killed in the Sandy Hook school shooting in Newtown, Conn., say they are honouring their daughter by fighting to end gun violence.

But Jimmy Greene and Nelba Márquez-Greene say the pain of their daughter's murder is not going anywhere.

"Sometimes I think it would feel absolutely normal if I saw her running around the corner into the living room right now. And the realization that's not going to happen and the weight that that thought brings is really, really paralyzing," Greene told CBC News in the parents' first Canadian interview about their daughter.

"There's an Ana-shaped hole in my heart that will always be there," said Márquez-Greene.

The Márquez-Greenes are just one of the families whose lives changed forever on Dec. 14, 2012, when a 20-year-old man, armed with an assault rifle, shot his way through the front doors of Sandy Hook Elementary School in Newtown.

He killed 20 children and six staff members before turning the gun on himself. One of the children was Ana. Her brother, nine-year-old Isaiah, was not injured.

The Márquez-Greene family had lived in Winnipeg for three years before moving to Newtown in July 2012.

Greene and Márquez-Greene are both Americans, but came to Canada to work. He taught music at the University of Manitoba, and she was a therapist at the University of Winnipeg. Ana thought of herself as partly Canadian, they say.

Ana 'lived out loud'

"She lived out loud. She was not self-conscious. She was so comfortable with herself," Greene said of Ana.

"She liked to sing and dance, without prompting, in front of people. She just loved being herself."

In her office, Márquez-Greene has a couple of mementos on the wall to help keep her going, like the last school exercise Ana did.

mi-marquez-greenes-1306

Nelba Marquez-Greene, left, and Jimmy Greene say they know gun law reform won't happen overnight, but they and other members of Sandy Hook Promise are in it for the long haul. (CBC)

"It was on the hopes and dreams board. It was Ana's hope and dream for the year, and her dream was to write stories, to write stories when she could," she explained.

On the same piece of paper, Ana drew a brown puppy face and wrote the words, "My Puppy. By Ana."

Márquez-Greene said Ana had been lobbying hard for a dog.

There is a poem written by her son Isaiah in her office as well. He wrote it for Mother's Day.

"The first line knocked me off my feet," she said. "It was, 'If my mom was in charge of the world, she would cancel fighting.' I hope I can honour my son by doing a bit of that through Sandy Hook Promise."

Catalyst for change

More than six months after the massacre, Ana's parents say they hope to turn their tragedy into a catalyst for change.

Márquez-Greene currently works for Sandy Hook Promise, an organization she and her husband helped create around a kitchen table with other families and friends of the shooting victims.

mi-ana-last-assignment-1306

Ana Marquez-Greene described her hope and dream for the year her last school exercise. The assignment is now posted at Nelba Marquez-Greene's office. (CBC)

Outraged and heartbroken, they formed the group just days after the shooting. Their goal: to end gun violence, lobby for more mental-health resources and support the victims' families.

"We don't want any more dead children, and eight dead children a day to gun violence is eight children too many. We can all agree on that," said Márquez-Greene.

The group has had some successes. In just five months, 200,000 people have signed on to the Sandy Hook Promise online, and the state of Connecticut has passed one of the toughest gun laws in the country.

However, there have been disappointments, too. In April, U.S. President Barack Obama's gun reform legislation failed to pass the Senate.

The parents know change does not come overnight, especially when it comes to a controversial topic like gun control, but Márquez-Greene said they are in it for the long haul.

"A change in gun laws will only happen after we shift the culture. That's all," she said.

Group doesn't want to ban guns

When it comes to gun law reforms, the Márquez-Greenes and Sandy Hook Promise do not want to ban guns.

They say they respect the U.S. Constitution's Second Amendment right to bear arms, but they believe some reform can help save lives.

Specifically, they would like to see laws passed mandating background checks for gun owners.

"Most people agree that should happen. Most people are surprised they don't happen," said Greene.

"Most people are shocked you can go to a gun show and, most often, not even show your driver's licence and walk away with any number of weapons. That makes no sense."

A recent poll suggests 91 per cent of Americans would support universal background checks.

The Márquez-Greenes say they would also like to see limits placed on the size of ammunition magazines.

Day of shooting still 'surreal'

Ana's father says the day of the school shooting is still a blur for him.

"To me, the events of the day seem surreal. It's hard to really have a clear picture of the events and what went on," Greene said.

"It's still hard to swallow, hard to come to terms with even six months later. The shock is still there."

Márquez-Greene said the family's faith in God helped them through the time when all the victims' families were told to gather in the town fire hall to hear the news that their loved ones were killed.

"I'm so grateful that we knew at that moment, as heartbroken as we are and were, that Ana was with Jesus and we get to see her again. And that's how we pulled through that fire house. I would definitely say that," she said.

"The hope that we'll be reunited one day, you know, that's comforting," said Greene.