"It got to where instead of saying why not do this, and why not do that, to just feeling sorry for him," Larry Underwood testified.
When FBI agents took his son away to question him about the disappearance of 10-year-old Jamie Rose Bolin, Larry Underwood said he actually smiled, because he knew his son was going to help if he could.
When he found out the grisly truth, the father said he could not believe it.
Earlier in the morning, jurors heard testimony from Underwood's aunts, who described him as an awkward and socially inhibited young boy, who never got any better as he grew older.
Gayle Coburn, Kevin Underwood's aunt from Emporia, Kan., testified that her nephew was always on the fringes, even when his cousins were playing.
"He was always reaching out wanting to play but not able to take the next step," Coburn said.
She recalled a trip she planned for Kevin Underwood to go to the Natural History Museum to look at dinosaurs, but said her nephew refused to go at the last minute.
"He said there would be a lot of people there," she recalled, adding that Kevin Underwood was always worried people would think he was weird or different.
"He was different," she said.