When cyclist Anna Moriah "Mo" Wilson was murdered in Texas, U.S. Marshals assigned to the case used a unique tactic to track down her suspected killer in Costa Rica and bring the fugitive to justice.

Kaitlin Armstrong is serving 90 years in prison for murdering professional up-and-coming gravel cyclist Anna Moriah “Mo” Wilson. It’s a story that drew international headlines because after being suspected of killing Wilson in Texas, Armstrong vanished – seemingly into thin air. The search for the suspected killer sparked what would become an international manhunt – first leading authorities across the United States, and then eventually to the beaches of Costa Rica.

In June 2022, one month after Armstrong disappeared, Deputy U.S. Marshals Damien Fernandez and Emir Perez traveled to Costa Rica. A source told them Armstrong could be hiding out in Santa Teresa. They knew finding Armstrong in the small, tourist-filled village was going to be a challenge – along the way, Armstrong used multiple identities and changed her appearance – even getting plastic surgery.

They hit dead end after dead end. After many intense days of searching for Armstrong with no luck, the U.S. Marshals decided to try one last tactic, hoping that her love of yoga would pay off for them.

“We decided we were gonna put an ad out … or multiple ads for a yoga instructor and see – what would happen,” Perez told “48 Hours” contributor Jonathan Vigliotti.

But after almost a week of hunting, even that didn’t seem to be working. Perez and Fernandez were about to head back to the States, when suddenly they got a break.