On Tuesday, Dave Poletti, 48, and his siblings were moving their elderly parents into an assisted living apartment in Pennsylvania when suddenly his cellphone rang, flashing an unknown number.
It was his son Brandon, a sophomore at the University of North Carolina, Charlotte. Brandon was whispering, and Dave struggled to hear. His son told him not to freak out, but there had been a shooting.
"On campus?" Dave asked.
"No, in my class," Brandon said.
The 20-year-old then said he had to go, and hung up the phone.
Dave called his wife, Sharon, then grabbed his brother's and sister-in-law's hands and began praying.
At the time he called his dad, Brandon was hiding in a closet across the hall from the classroom where, just minutes earlier, he'd been giving a presentation to his Science, Technology, and Society class when a former student opened fire.
Two students — Riley Howell, 21, and Ellis "Reed" Parlier, 19 — were killed. Four others were injured, three critically.
Brandon hid under his desk when the shooting began — only running out with other students into the nearby closet when there was a sudden pause in the gunfire.
"That could have been when Riley did what he did," Dave said.
Dave said he had read about Howell's actions — the muscly kid who loved the outdoors and snowboarding had charged at the shooter after he began firing, helping to take him down — and felt compelled to contact BuzzFeed News to say publicly how grateful he was for Howell's response.
"Riley Howell, I believe, is a big reason my son is alive," Dave said.
Charlotte-Mecklenburg police Chief Kerr Putney has credited Howell with helping save his classmates.
"He took the assailant off his feet," Putney said at a press conference Wednesday. "Unfortunately, he gave his life in the process. But his sacrifice saved lives."
The Polettis wants Howell's parents to know how thankful they are.
"We are grieving for them and want to thank them for raising a son who gave his life for others," Dave said. "We are truly shaken, yet indebted to his heroism."
Sharon, 51, agreed: "I hope they know, each and every parent and kid in that class feels the same way: extremely sorry for their loss but grateful for who he was and what he did."
Brandon, a computer science major, had just landed his first internship, working for Duke Energy over the summer. His class where the shooting took place is about "the appreciation and understanding of science and the public policy issues related to science and technology," according to the subject description.
When the gunfire began, "he thought it was a drill, until he saw the casings," said his father. After he fled, Brandon borrowed a classmate's cellphone to call his parents.
Sharon had her phone charging in another room, and when she noticed the missed call from an unknown number, she assumed it was a spam call. She's grateful her husband happened to pick up, realizing how easy it would have been for no one to answer and how panicked they would all have been if they'd seen the story on the news and not heard from Brandon.
"It was surreal to be talking to him while it was going on," Dave said.
Dave has spent the last three days going over in his head what could have happened, finding himself in constant tears. “Every 15 to 20 minutes, I think: ‘I could have just lost my son,’” he said. “You’re elated your son is OK, but...it’s mixed.”
Sharon agreed. The night of the shooting terrified her as a parent, "but in some ways the next morning was harder."
She thought of the families of the dead and injured, realizing just how different their morning must be to hers. "I couldn’t get over that. I still have a hard time with that," she said, choking up.
The incident has left Dave asking a series of questions: Why did the shooter choose that particular weapon? Where are kids getting their morality from? How did the death of the shooter's mother from cancer affect his life? Why is his own child unhurt when the boy sitting next to him was hit and injured by a bullet?
“I wasn’t even prepared for how I felt afterwards,” Dave said. “It tore you in half just to think that what’s going on in this country and this world could affect you that directly.”
On Wednesday he began driving home to Southport, North Carolina. Brandon drove the three and a half hours from Charlotte, even though he hadn't originally planned to go home this weekend because gas is expensive and his college funds are tight.
"It was that need to have him here, even though we knew he was OK," Sharon said.
The Polettis say they will never forget that their good fortune may be thanks to another family's heartache.
“I'm absolutely grateful and amazed, thankful and torn, all at the same time, for what he [Howell] did,” Dave said. “That’s an amazing sacrifice.”
Brandon Poletti is 20 years old. A previous version of this story misstated his age.