Through the days of waiting to hear word about their beloved mother and grandmother, Phillip and his family were drawn to the site of the bombing.
Even after workers unearthed her remains, the Thompsons stayed.
Phillip worked with former mayor Ron Norick to plan the Oklahoma City National Memorial and Museum grounds.
When the marathon began in 2001, Phillip ran. Later that year, he flew to New York City to work with families dealing with the tragedy of Sept. 11.
But nothing proved more therapeutic than watching his daughter compete on Sunday.
"You look back at all the pain you went through and the difficult times, but now you're in a really good place in life and you're able to see the next generation get older and enjoy this moment,” he said. "We think about (Virginia) today, but in a great way. We're not sad today at all.
"It's just a really special, heartfelt moment.”
Desiree ran 6.2 miles to begin the race. Three hours later, she ran another 400 yards — the marathon's final stretch — holding hands with her teammates.
After she reached the finish, she sought out her father. They embraced.
"We've all gotten closer and stronger because of her,” Desiree said. "We have old videos we watch. We talk about the happy times.
"It makes me feel like I really knew her.”