A homeless man who murdered promising Iowa State University golfer Celia Barquín Arozamena while she was playing a round will spend the rest of his life behind bars without the possibility of parole, a judge ruled Friday.

Golfer Celia Barquin Arozamena Iowa State Athletics

Collin Daniel Richards, 22, pleaded guilty in June to the first-degree murder of the Cyclones standout golfer Barquin Arozamena before he appeared in front of Story County Judge Bethany Currie.

Richards' life-without-parole sentence was mandated after the guilty plea.

“Even if I had discretion to choose a sentence, based on the facts of this case I believe the sentence is appropriate,” Currie said.

Collin Daniel Richards. Story County Iowa Jail via AP file

Richards stabbed Barquín Arozamena, 22, to death on Sept. 17 while she was playing at Coldwater Golf Links near the Iowa State campus in Ames.

The killer had been staying at a homeless encampment in nearby woods.

"I want you to know how sincere I am I want to show remorse for stripping a life from society worse from a loving family," Richards wrote in a letter to the court this month. "I want the family and you know to know I'm sorry."

Barquín Arozamena studied civil engineering at Iowa State and was the Big 12 Conference player of the year in 2018.

Heartbroken over what happened to #CeliaBarquinArozamena I had the pleasure of meeting her and I know she was a special person. Sending my thoughts and prayers to her family and loved ones in this difficult time — Sergio Garcia (@TheSergioGarcia) September 18, 2018

A native of Puente San Miguel, Spain, Barquín Arozamena's slaying stunned the Spanish golfing community.

Masters champion and Spanish golf icon Sergio Garcia said he was "heartbroken" by her death. One of her prized possessions was a picture of herself as a young child with Garcia.

Days after her murder, Garcia said he'd dedicate a round of the Portugal Masters to Barquín Arozamena's memory — and he shot a 5-under 66.

“It was nice to shoot a nice score and dedicate it to Celia,” Garcia said that day.