"I cried a lot. There was a lot of disbelief. A lot of taking it day by day," Rosenbeck said.
As time passed, the cloud of sadness began to dissipate. But the memory of their mother remained.
"It's strange, you know, when you wake up and it's an average day and you hear a song or see a picture, and you realize: 'I'm 18 and I'm never going to see my parents again,'" Magnano said. "To lose someone who's supposed to be around for the next 40 or 50 years of your life, it's a strange feeling."
Both he and Rosenbeck still draw strength from their mother.
At first, Rosenbeck said, "I couldn't think of her in a happy way. I couldn't think of her without being sad. Now I can think about her and feel happy." She now keeps a photograph of her mother on her desk at work.
Magnano said he has come to terms with her death.
"Every once in a while I get upset about it," he said. "But she made us stronger people. Just the memory of her keeps us going."
Looking ahead is sometimes difficult for Rosenbeck.
"It's very hard thinking about getting married and having kids when my mom's not here. I feel like growing up, becoming an adult, that poses enough issues as it is. But now my confidant and best friend is gone," she said.
Still, the bond she remembers sharing with her mother gives her strength.
"She taught us to be strong and go after things. I don't want anything we went through to be in vain," Rosenbeck said. "I want to be stronger than that."