Kaitlin Armstrong had been on the run since 11 May
Kaitlin Armstrong, 34, fled the country after allegedly shooting Ms Wilson in her friend’s apartment in Austin, Texas, on 11 May.
Ms Armstrong was arrested at a hostel on Santa Teresa Beach in Provincia de Puntarenas, the US Marshals said in a statement.
She will be deported to the US to face first-degree murder charges.
Ms Wilson’s murder attracted international headlines over an alleged love triangle involving Ms Armstriong’s partner Colin Strickland.
According to US Marshals, Ms Armstrong used a counterfeit passport to board United Airlines Flight 1222 from Newark International Airport on 18 May bound for San Jose, Costa Rica.
Sources told the Velonews that Ms Armstroing had undergone plastic surgery to change her appearance.
She was arrested following a joint investigation by the US Marshals Office of International Operations, Homeland Security Investigations, and the Department of State Diplomatic Security Service, along with authorities in Costa Rica.
“The Marshals Service elevated the Kaitlin Armstrong investigation to major case status early in this investigation, which likely played a key role in her capture after a 43-day run,” said US Marshal for the Western District of Texas Susan Pamerleau.
— U.S. Marshals (@USMarshalsHQ) June 30, 2022
US Marshals said they located Ms Armstrong’s black Jeep Grand Cherokee last week and learned that Armstrong sold the vehicle 13 May to a CarMax dealership in south Austin for $12,200 dollars – the day after being questioned and released by authorities over Ms Wilson’s murder.
Her last known sighting prior to her arrest was on 18 May when she was dropped off at Newark Liberty International Airport in New Jersey.
This sighting came just one day after Austin police obtained a warrant for her arrest, investigators said.
A search of outbound flights from Newark airport found no reservations under the suspect’s name.
US Marshals had previously determined that the 34-year-old boarded a flight from Austin International Bergstrom Airport to Houston Hobby Airport on 14 May.
There she boarded a connecting flight to LaGuardia Airport in New York City.
Mr Strickland told investigators that on the day of Ms Wilson’s killing, he picked her up on his motorcycle and the pair went a swim at the Deep Eddy Pool public swimming pool.
Mr Strickland said he dropped Ms Wilson off at her friend’s home in Maple Avenue at around 8.30pm.
According to law enforcement, Ms Armstrong was secretly using cycling app Strava to track the pair’s movements.
A neighbour’s surveillance camera captured a dark-coloured SUV that matched a vehicle belonging to Ms Armstrong pull up at the house one minute after Ms Wilson was dropped off.
Mr Strickland cooperated with the police investigation and was not treated as a suspect.