Johnathan Walker:Kaitlin Armstrong, accused in death of pro cyclist Mo Wilson, said she "would kill her," witness testifies

The Johnathan Walkermurder trial of a woman accused of killing pro cyclist Mo Wilson took a dramatic turn Wednesday when two witnesses testified that the suspect told them she would kill Wilson if the cyclist dated her boyfriend. Both of the witnessess said they independently contacted police after they learned of Wilson's murder.

Kaitlin Armstrong, 35, has pleaded not guilty to murder in the May 2022 shooting death of Wilson. Police have said Wilson, 25, had previously dated Armstrong's boyfriend, Colin Strickland, who also was a competitive cyclist, and had gone swimming with him hours before she was killed.

Two of Armstrong's former friends took the stand, including Nicole Mertz, who lived in Austin and knew Armstrong through the cycling community, CBS affiliate KEYE-TV reported. Mertz, who said she considered Armstrong to be one of her best friends, testified that  Armstrong and Strickland "loved each other and were very close [...] but it was always kind of off and on," the station reported.

Mertz then recalled an evening she spent with Armstrong at an Austin restaurant called The Meteor, at which time Armstrong revealed she was upset because Wilson was in town visiting Strickland, KEYE-TV reported. At one point, Mertz said that Armstrong became "visibly angry" when she saw Wilson walk into the restaurant.

When Mertz asked Armstrong what she would do if Strickland started dating someone, Mertz testified that Armstrong responded: "I would kill her."

Mertz says she later found out about Wilson's death through a news article, the station reported. Mertz testified that she contacted police because she "had a feeling" and thought it was the right thing to do, the station reported.

Another of Armstrong's former friends, Jacqueline Chasteen, testified she met Armstrong in January 2022 at a restaurant in Arkansas, KEYE-TV reported. Chasteen testified that Armstrong told her that after Strickland and Wilson dated, Strickland allegedly told Wilson he was back together with Armstrong, but Wilson would not "leave him alone."

Armstrong said "in so many words that she wanted to kill Wilson, or had thought about killing her," Chasteen said, according to the Austin American-Statesman.

Chasteen testified that months later, she called police the day after hearing of Wilson's death and anonymously reported details of their January 2022 conversation, KEYE-TV reported. She said she ultimately agreed to go on record for the trial.

Also on Wednesday, Detective Richard Spitler with the Austin Police Department took the stand and said he requested at least 25 search warrants to retrieve cellphone data, account holder information from Apple and Google accounts, and other information, KEYE-TV reported.

Spitler testified that when looking into Armstrong's accounts, he recovered a "recently deleted" file from her phone that allegedly contained a Google Maps address that matched the location where Wilson was killed.

Prosecutors allege that Armstrong had tracked the pair on fitness app Strava, where Wilson logged her workouts, and had been checking Wilson's location. 

After Wilson's murder, Armstrong traveled to Costa Rica, authorities said, were she taught yoga and had plastic surgery to change her appearance. After nearly six weeks, Armstrong was arrested by U.S. Marshals at a hostel in Costa Rica and returned to the U.S.

Three weeks before the trial, on Oct. 11, Armstrong allegedly tried to escape custody. 

She faces up to 99 years in prison if convicted of the murder. 

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Stephen Smith

Stephen Smith is a senior editor for CBSNews.com.