Peter Lanza was the only person who could answer their questions.

The father of Adam Lanza, the 20-year-old man who shot 20 children and their six teachers at Sandy Hook Elementary School, met face-to-face with the victims’ parents recently, AP reports.

"Adam's gone and his mother's gone, and those are the two people that could give us the most information to the questions that all of us have," Robbie Parker, whose daughter, Emilie, was killed, told CBS.

He and his wife, Alissa, do not blame Lanza’s father for their daughter’s death.  

"I don't feel like he should be held responsible for what happened that day," Alissa told CBS. "That was not ultimately his decision to do that, so how can I hold him responsible? Were there missteps in the raising of his son? Possibly."

Jill Cottle Garrett, Alissa Parker’s sister, told the Danbury News-Times that the meeting helped the couple cope with their loss.

"It was just something they needed to do," she said.

In the Parkers’ interview with “CBS This Morning,” the couple declined to comment on what Peter Lanza said about his son, AP reports. A motive for the mass shootings has yet to be determined, but authorities said Adam Lanza expressed an interest in other rampages and literature on the topic, the news outlet reports.

Robbie Parker was the first parent of a child killed to speak to the public about the massacre. On Dec. 15, a day after the shooting, Parker spoke at a news conference about his daughter.

“The world is a better place because Emilie was in it,” he said about the eldest of his three children. "I'm so blessed to be her dad."

The couple moved from Utah to Newtown, Conn., a year before the shooting. The family has since moved back, according to the Danbury News-Times.