Collin Richards, 22, sent a letter to District Judge Bethany Currie on Tuesday saying he wants "to show remorse for stripping a life from society."
"I want family and you to know I'm sorry," Richards wrote in the letter, which was published by the Des Moines Register. "I also want you to know change is my mission [illegible] new life is my goal."
Richards added in his handwritten note he plans to use all possible resources, stating: "If there is anything I can do I will."
Barquin Arozamena, an international student from Spain studying at Iowa State, was found dead at Coldwater Golf Links in Ames in September 2018. She had sustained multiple stab wounds. Authorities linked Richards to three kitchen knives investigators said were used in connection with the golfer's death.
Richards pleaded guilty in June to first-degree murder. He faces a mandatory life sentence, according to the Des Moines Register.
Barquin Arozamena, a native of Puente San Miguel, Spain, became the second women’s golfer at Iowa State to earn medalist honors at a conference tournament when claiming the 2018 Big 12 Championship. She was one of the most accomplished golfers in the university's history.
Fox News' Katherine Lam and Kathleen Joyce contributed to this report.