Shortly after sending the text, Barquín Arozamena, 22, was golfing alone on a course in Ames, Iowa, working on how to take her game to the next level, when authorities say she became the victim of "a random act of violence" allegedly perpetrated by a man who had recently told an acquaintance that he wanted to "rape and kill a woman."
As police recovered the body of Barquín Arozamena from a pond on the Coldwater Links public golf course near Iowa State University in Ames, Martens began to get news of her former star player's murder on her phone.
"You can't believe it. There started being some reports, Ames Police reports at Coldwater. It's kind of like you don't know what's going on, but then we couldn't get ahold of Celia," Martens said in a tearful news conference Tuesday evening, after she and her golf team withdrew from the Ann Arbor tournament and returned to Iowa to mourn the death of the reigning Big 12 champion golfer.
In the text message to Martens, Barquín Arozamena wrote, 'Love seeing my Cyclonitas on top. Keep it up, girls."
"That really typified who she was," Martens said.
The heinous death of Barquín Arozamena sent shockwaves all the way to her hometown of Reocín, Spain, where a moment of silence was held in front of City Hall and civic leaders called for three days of mourning.
"I would like you to remember her as a fighter, as she always proved in sport and outside of it as well," Barquín Arozamena's brother, Andre Barquín, said at a vigil for his sister Tuesday in Torrelavegua, Spain.
A friend of Barquín Arozamena in Spain told ABC News Wednesday that he found the circumstances of her death unfathomable.
"I can't believe she crossed paths with this monster. It's just really bad luck," said the friend, Miguel, 23, who asked that his last name be omitted.
"I hope he will be severely punished," he said of the woman's alleged killer. "She never did anything wrong."
Miguel, who is also a golfer, said he trained with Barquín Arozamena in Madrid, where she was studying before she moved to Iowa for school.
"Her life was golfing," he said. "She was passionate. Even [when] she was very young she was winning many medals and championships."
News of her death also caused pain for Barquín Arozamena's favorite golfer Sergio Garcia, the 2017 Masters Champion.
"Heartbroken over what happened to #CeliaBarquinArozamena," Garcia wrote on Twitter. "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."
After Garcia won the Masters, Barquín Arozamena, was one of the first to send him a congratulatory note on Instagram. In the post, she attached a childhood photo of her meeting the golfer, who inspired her to follow in his footsteps.
"You are a true champion," Barquín Arozamena wrote of Garcia. "That was amazing. #TheMasters2017 Spain is proud of you!"
Martens said that when Barquín Arozamena won the Big 12 Championship, Garcia returned the favor, tweeting her congratulations.
"She also loved Spain and she loved Sergio," Martens said. "She basically started crying on hole 13 of the Masters. She knew he was going to win. She already started crying because she was so thrilled."
Investigators in Iowa are still trying to determine why suspect Collin Daniel Richards, 22, who police said has no known address, targeted Barquín Arozamena on Monday morning.
She was stabbed multiple times — suffering wounds to her torso, neck, and head — before her body was dumped in a pond on the golf course, according to a criminal complaint against Richards.
Richards was charged Monday with first-degree murder and is being held in jail on $5 million bail.
"I hope people reserve judgment until after the trial," Richards' attorney Paul Rounds, of the Story County Public Defender's Office, told ABC News when reached by phone on Tuesday. He declined to comment further.
Richards, who has a lengthy criminal history, had purportedly told an acquaintance recently that he wanted to "rape and kill a woman," according to the criminal complaint.
He was arrested on Monday after approaching police on a tent encampment next to the Coldwater Links public golf course. He had several fresh scratches on his face consistent with fighting and was attempting to conceal a deep laceration to his left hand, the criminal complaint read.
After allegedly killing Barquín Arozamena, Richards showed up at an acquaintance's home near the golf course covered in blood, sand and water and asked if he could take a bath, according to the complaint.
Martens said she has spoken with Barquín Arozamena's mother by phone.
"It was very hard, but I guess the thing that meant the most to me was she said, 'Celia was very happy every day that she was there [at Iowa State] and even though all this has happened, if we had to decide all over again, we would still send her to Iowa State,'" Martens said.
She broke down in tears as she recalled how she recruited Barquín Arozamena.
"Everyone had told her that if you want to play college golf you have to go to the South. When I met with her and her mom, when I watched her at a tournament in France, her mom and I just hit it off right away. We just got along great and her mom said, 'I trust you. I want my daughter to go to Iowa State,'" Martens said.
Barquín Arozamena had completed her eligibility as a student-athlete and was named Iowa State's female athlete of the year for 2018. After winning the European Amateur Championship in June in the Netherlands, she turned pro and qualified for the U.S. Women's Open in Alabama, one of the LPGA Tour's majors.
"The spotlight is on her because of her golf. But what makes it so hard ... is who she was as a person and how much she meant to me personally and to our program and to all of her teammates and to everyone at Iowa State," Martens said.
A vigil in Barquín Arozamena is scheduled to be held Wednesday at 7 p.m. on the Iowa State campus. On Saturday, the school will honor her at a football game at the school's Jack Trice Stadium, which is across the street from the golf course where her body was found.
The Iowa State Cyclones football team plans to wear their yellow jerseys to commemorate Barquín Arozamena.
"Yellow is her favorite color," Martens said.