The man accused of killing Celia Barquin Arozamena is pleading not guilty. Online court records show Collin Richards, 22, entered his written plea in Story County Court Monday morning. His in-person arraignment scheduled for Monday was cancelled. Richards is charged with first-degree murder in Barquin Arozamena's death at an Ames golf course last month. Police say Richards, who's considered homeless, stabbed the Iowa State engineering student and champion former golfer several times September 17th. Search warrant information released last week shows police found three knives that could be connected to the killing. Investigators also say Richards was found with a cut on his hand consistent with stab marks on Barquin Arozamena's body. He's being held in the Story County jail on a $5 million cash-only bond.