Roxanne and Dennis Simmonds knew their son as fearless and strong from the day he was born.
"D.J. came out with shoulders of a linebacker," Roxanne says. "He was the first baby I saw that had muscles."
"He wasn't really afraid of anything," Dennis says.
At night, young D.J. would take the dog with him and circle the entire house, to "make sure there's nobody on the grounds," Dennis says, laughing. "I used to say, 'D.J. where you going? It's late.' He would say 'I'm doing a perimeter search, Dad.' "
So when D.J. told his parents he was entering the police force, they were hardly surprised.
But after his work brought him to the front lines of the horrific events that surrounded the Boston Marathon bombing, the son who returned home wasn't quite the same.
Four days into a manhunt for the suspects, in the early morning hours of April 19, 2013, police confronted the bombers on a suburban street in nearby Watertown. Among them was Boston Police officer D.J. Simmonds.
"You know, with the kids," Roxanne says, "I have this thing that I have to talk to them every day. But after the bombing, he called me and he said, 'Ma. I'm not going to be able to talk to you all the time right now.' "
The confrontation eventually led to a shootout between the bombers and police. "D.J. and his partners were able to corner the brothers," Roxanne says. "And they were some of the first ones on scene."
Roxanne and Dennis recall seeing a clip of the showdown on TV — that's when they recognized their son's voice. "It instantly sent chills up to my back," Dennis says.
A homemade bomb thrown by one of the Tsarnaev brothers detonated near D.J., knocking him off his feet.
"We knew he had a concussion, but he said he was fine," Roxanne says. "But, we knew something was a little different."
"Yeah, he was quiet," Dennis says.
"He'd said when he closed his eyes he would see the bombs," Roxanne says. "I will never forget the day he came downstairs. I was in my bedroom and he stood at the door and said, 'I'm afraid of the dark.' I didn't know what to say. His eyes looked like — he was like a kid again. That was the only vulnerability that D.J. ever showed."
"He died a year later," she says.
Their son had suffered a brain aneurysm. D.J.'s death, in April 2014, was linked to head injuries he sustained when an explosive thrown by one of the Tsarnaev brothers detonated near him.
"He used to [lie] on my lap and I used to rub his head," Roxanne says. "I miss that. I miss dialing his phone number. I miss dialing that every day. I've loved him since the moment I saw him as a little baby linebacker and I love him more and more every day."
Audio produced for Morning Edition by Liyna Anwar and Jasmyn Belcher Morris.
StoryCorps is a national nonprofit that gives people the chance to interview friends and loved ones about their lives. These conversations are archived at the American Folklife Center at the Library of Congress, allowing participants to leave a legacy for future generations. Learn more, including how to interview someone in your life, at StoryCorps.org.