About 70 students take the engineering course that Jim Alleman teaches three afternoons a week at Iowa State University, but he always looked forward to seeing one in particular.

Celia Barquin Arozamena “genuinely had a warmth about her. Her smile, it was wide and it was friendly,” the longtime professor said.

When Alleman looked out at his class early Monday afternoon, “it clicked that she wasn’t there. I thought maybe she had a golf tournament or something.”

FULL COVERAGE:Stories, photos and videos related to former Iowa State golfer's slaying

Alleman later learned that Barquin Arozamena was dead, killed, police say, by a homeless stranger who stabbed her before leaving her body in a pond at Coldwater Golf Links. Collin Daniel Richards was charged with first-degree murder in her death.

"It's a terrible, tragic and senseless loss," Wendy Wintersteen, Iowa State’s president, wrote in an email to students and university employees Tuesday.

Barquin Arozamena, from a small village in northern Spain, was an acclaimed golfer and 2018 Big 12 Conference women’s golf individual champion. She won the European Ladies’ Amateur Championship and this summer competed in the U.S. Women’s Open.

But she was more than a golfer, Alleman said. She was a smart, personable young woman who "had a vision of where she wanted to go in life. … I've been teaching for 40-some years, and I never had an athlete in my classroom who had that type of talent.”

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Barquin Arozamena knew little English when she arrived on the Ames campus in September 2014, nearly a month after classes started. She was late because she was competing in a golf tournament.

"No orientation, no first or second week of classes," Barquin Arozamena said in a video produced by Iowa State Athletics and posted on Facebook five months ago. "Our assistant coach at the time, she picked me up from the airport and just drove me here and she's like, 'This is your schedule, this is practice, this is your student ID.'"

The next day, Barquin Arozamena didn't make it to classes because she couldn't find them. "… lots of people looked weird at me because they don't understand me," she said in the video.

A teammate helped her to her classes.

Barquin Arozamena, who turned 22 in July, picked a difficult major — civil engineering — and was on track to graduate in May, ISU officials said.

ISU athletics director Jamie Pollard recalled when Barquin Arozamena arrived on campus.

“Celia was trying to decide what path of engineering to go into,” he said. “Someone advised her that civil engineering was too hard. She said, ‘Thanks, you made my decision.’ She said she was going civil engineering.”

Alleman said he had Barquin Arozamena in three classes: Introduction to civil engineering, basic environment and sustainability.

Alleman said he never asked Barquin Arozamena how she became interested in civil engineering but thinks she might have been inspired by a road the Romans built centuries ago that went through her village in Spain.

“She was very interested in the road,” Alleman said.

Barquin Arozamena was named three times to the All-Big 12 academic team.

Her family lives near Puente de San Miguel (Cantabria), Spain, according to El Pais newspaper in Spain. The mayor of the town decreed a time of mourning through part of Friday.

“It has been an impressive blow,” Pablo Diestro, the mayor, told the publication.

"With the character that she had, a hard worker, a good student. … She was a girl who, when she was around here, (we) always saw her doing sports, studying, always very focused on these things.”

Said Alleman, the ISU professor: "She is … was just remarkable for what she was able to do."

Linh Ta and Randy Peterson contributed to this article.