PLEASANTON, Calif. (KGO) -- Jen Yao sobbed and trembled as she said, "It takes every molecule in my body to stay in the moment. And every fiber of my being is taking care of our kids during this time."
She is the wife of missing jogger Philip Kreycik, who went for a run Saturday in Pleasanton and never returned.
They have a 3-year-old son and a 10-month-old baby.
"I can remember when he was a little kid and the things I did with him, to see him doing those with his kids. He loves to throw his kids up in the air," Keith Kreycik, Philip's father said somberly.
In an exclusive interview with ABC7 News, they recalled the disbelief, the panic and now the agony of walking the hills searching for 37-year-old Philip.
Family and friends call him Phil.
He left Berkeley Saturday morning for what was supposed to be a brief run in the Pleasanton hills, and he never showed up to pick up his family in Stockton a few hours later. It was 106 degrees outside.
The trail he intended to take a run on was someplace he wasn't familiar with.
What does the family think happened?
"Well, I personally think he had got into a hot weather situation, maybe didn't have enough hydration. And we're concerned he made it out of the park," Keith Kreycik said.
Yao added tearfully, "I know in my heart of hearts he's out there. He's out there and he's alive and he's waiting for us. And maybe he's dehydrated, maybe injured, delirious."
VIDEO: Bay Area volunteers refuse to give up search for missing runner
Kreycik put out a public plea saying, "One of the things we want to do is make sure that everybody that has got property that's remotely close to the park boundaries, please search your outbuildings and your barns, your ditches, your backyards, wherever a person who is not in their right mind might try to hide."
No evidence has been found yet to indicate where Philip Kreycik might be. The family does not suspect foul play. They say he is a brilliant guy working with PG&E on infrastructure for transportation electrification.
Even if the formal search and rescue effort is scaling back after 5 days of trying, they are building a community army of volunteers to keep hope alive.
His dad said, "I don't think I'll ever personally stop searching."
"He's extremely fit mentally and physically, and we ask people to have faith with us that he is out there alive waiting for us," his wife said. "We ask people to help us and we will bring him home together."