Race organizers told NewsChannel 3 in Norfolk that the EMS call came in as a cardiac situation.
Wegner collapsed at mile marker one near the intersection of Pacific Avenue and 24th Street. An off-duty Virginia Beach police officer and bystanders rushed in to try and help him.
Wegner was a member of the 2013 Richmond Marathon training team. He ran the marathon in 2011 and ran half marathons in 2010 and 2012, according to the Richmond Sports Backers.
Sam Wegner said his father loved everything about running.
"First it was half marathons, then marathons," he said.
"The doctor came in and said regardless of what they do, they don't think he's going to survive," said Sam.
Sam said his dad lived a healthy lifestyle, but had suffered three heart attacks prior to Sunday's run. He said his dad didn't start running until 2009, after his heart attacks and ran his first marathon in 2011.
Sam used to be a runner himself. He said he and his brothers are planning to run a marathon in honor of their dad.
If you knew Wegner and have thoughts or memories you'd like to add, please email WTVR.com.