By Anumita Kaur and Praveena Somasundaram

January 28, 2024 at 9:24 p.m. EST

After Kaitlin Armstrong was accused of killing professional cyclist Anna Moriah Wilson over a disastrous love triangle in 2022, she fled to Costa Rica with a fraudulent passport, hiding out in a touristy beach enclave for more than a month while an international manhunt sputtered.

But even fugitives sometimes need jobs.

Armstrong eventually answered an ad seeking a yoga instructor. Unbeknownst to her, it was placed by the U.S. Marshals Service, investigators revealed to CBS’s “48 Hours” this weekend. It was authorities’ last resort to lure her out of hiding, and Armstrong’s response led them right to a beachside hostel.

Armstrong, 36, who was found guilty of first-degree murder late last year in Wilson’s slaying, has been serving a 90-year sentence. Her month-and-a-half-long disappearance following Wilson’s slaying drew national attention and rocked the cycling community, which mourned the death of 25-year-old Wilson, an up-and-coming gravel cyclist. Interest only mounted when authorities said they suspected Armstrong had shot Wilson over a romantic entanglement with another pro cyclist, 35-year-old Colin Strickland.

Authorities spent weeks on the hunt for Armstrong, as the case escalated from police in Austin — where the murder happened — to federal investigators.

U.S. marshals, in charge of apprehending federal fugitives, eventually zeroed in on a touristy beach town in Costa Rica, where Armstrong was suspected to have fled. They staked out the town and spent days asking locals about her, but she proved hard to find, investigators told 48 Hours — she was using a fake passport, had gotten plastic surgery, changed her hair and taken on different names.

“We decided we were gonna put an ad out for a yoga instructor and see what would happen,” Deputy U.S. Marshal Emir Perez told 48 Hours. They received no response to their post for almost a week, he said.

Just as the marshals were ready to head home, “we got a bite,” Perez said. Somebody responded to their ad identifying herself as a yoga instructor and wanted to meet. “And we said, ‘This is our chance!’”

It was Armstrong.

She was arrested at a hostel on Santa Teresa Beach, escorted back to Texas, charged and held in jail. Her trial began and concluded in November 2023.

Armstrong’s run from authorities began in spring 2022. The yoga teacher and real estate agent was living with her boyfriend, Strickland, in Austin at the time, The Washington Post reported.

Wilson was staying at a friend’s home in Austin, ahead of a race she planned to complete in that weekend. Wilson and Strickland had been briefly romantically involved in 2021, while he and Armstrong were split. But Armstrong and Strickland later rekindled their relationship, and Armstrong seemingly viewed Wilson as a romantic rival — shaking with rage when she found out the pair were still in touch, and later warning Wilson to stay away from Strickland, The Post reported.

On May 11, 2022, Wilson met up with Strickland to go swimming. After having dinner, Strickland dropped Wilson off at her friend’s home, The Post reported. A minute later, what appeared to be Armstrong’s car stopped next to the same residence, according to the police affidavit.

When Wilson’s friend arrived home that night, she found Wilson lying on the bathroom floor, bleeding from multiple gunshot wounds.

Authorities interviewed both Strickland and Armstrong the next day — Armstrong offered no explanation as to why her car was there that night. On May 17, investigators found a ballistic match between shell cases recovered at the scene and a pistol that Strickland had previously bought for Armstrong, and Austin police issued an arrest warrant.

But by then, Armstrong — last spotted at Newark Liberty International Airport in New Jersey — had vanished.

A month later, the U.S. marshals arrived in Santa Teresa, Costa Rica, in pursuit of Armstrong following a source’s tip, they told 48 Hours. Many of the town’s residents looked similar to Armstrong, like foreign tourists on a tropical getaway, they said, complicating the task. The investigators even sent one of their operatives to the local yoga classes, in hopes they would spot Armstrong.

“We made friends with people there that would send us pictures. Oh look, I — I think I saw her at this restaurant yesterday and she’s in the back in the background of a photo that I took, stuff like that,” said Deputy U.S. Marshal Damien Fernandez.

Eventually, the investigators posted on a local Facebook page. “Just saying, hey, we’re at this hostel, we’re looking for a yoga instructor as soon as possible. Please contact us at this number,” Fernandez told 48 Hours.

After days with no responses, Armstrong replied.

Perez, disguised as a tourist, approached her at a local hostel alone to get a closer look at her, and confirmed she was the fugitive they had been after.

“He gets in the car, and he is like, ‘That’s her. She’s in there,’” Fernandez said.

Armstrong is serving her sentence at Plane State Jail in Dayton, Tex.