A self-described laid-back guy, Koch was anything but during the closing. He was passionate, loud, and full of expression.
The jurors and those in the gallery saw a much different side of him. It's because, he says, he believed in Kathleen Savio's case.
"I did feel proud about giving that closing argument because the believability in it from the get-go was always there," Koch said.
He talked about the challenges in this case and how he couldn't have done any of it without States Attorney James Glasgow and the entire team dedicating countless hours to this case.
"We were all free to express our opinions and our views, and the counter opinions from the others," he said. "It wasn't just the four of us. We had a support staff that was with us on those late nights on the weekends doing research and looking at case law. I guess what I can say is, again, when you believe as strong as we believed in, the teamwork was there."
Faced with mostly hearsay testimony, Koch knew it was going to be a tough fight, but he never had any doubt about the outcome.
"We knew this case, we knew the facts in this case, we believed in this case so through all of the issues, we knew we believed strongly in this case ," he said. "We knew if we presented it, the jury would find justice and find him guilty."
Then five and a half weeks of testimony came down to one moment.
"It's always that last second of waiting the anticipation for the jury to rise, foreman to hand paperwork, waiting for the moment, sense of relief it was everything we hoped it would be and everything we fought for," he said.
Afterwards, prosecutors congratulated each other, then met with the savior family. It was a moment Koch wants to keep private, but says it was a good moment, one that justified all the time spend on this case and away from his family.
"This was really about the Savio family and we're thankful the result was a guilty verdict it brings justice and hopefully closure for the Savio family," Koch said.
What's next for Koch?
He's taking time to relax with his family, attend Saturday night's White Sox game, coach his kid's soccer team, and then back to his courtroom on Monday.