New details have emerged after the arrest of Caitlin Armstrong, who has been formally charged with first-degree murder in the death of cyclist Moriah Wilson. According to Deputy U.S. Marshal Brandon Fila, Armstrong used several aliases while on the run, but confessed her true identity, partly due to fatigue, after she was captured and arrested by foreign officials in Costa Rica after a 43-day fugitive investigation.

"I would say she was exhausted. When I ran into a uniformed police officer in Costa Rica, I recognized her immediately. She didn't tell me her real identity at first, but when she was taken into custody and questioned, a few minutes later, she finally confessed to her real identity," Fila said at a press conference Thursday at the U.S. Federal Courthouse in Austin.

"So I think that's what prompted her to come forward. But it took a little while for her to reveal herself."

Armstrong is being held in the Travis County Jail on $3.5 million bail. She is charged with first-degree murder, unlawful flight to avoid prosecution, and misdemeanor theft of unrelated services in connection with Wilson's death.

Her first court appearance is scheduled for July 20.

Wilson was shot and killed on May 11 at her East Austin home in a case currently under investigation by the Austin Police Department (APD); the APD issued an arrest warrant for Armstrong on May 17 in connection with the murder investigation. However, later, with the help of the U.S. Marshals Service Lone Star Fugitive Investigation Unit, it was learned that she sold her black Jeep for $12,200 on May 13 and left Austin-Bergstrom International Airport on May 14. She then traveled to New York's LaGuardia Airport via Houston Hobby Airport.

According to authorities, Armstrong fraudulently obtained another person's passport and fled the United States from Newark Liberty International Airport in New Jersey to San Jose, Costa Rica.

Fila noted at a press conference that the passport belonged to "someone closely associated with her."

Marshals confirmed that they found and arrested Armstrong on June 29 at a hostel in Santa Teresa Beach, Puntarenas, Costa Rica, after a 43-day search for the fugitive.

Fila said authorities drove her six hours from the Santa Teresa Beach location to San Jose, where Armstrong was detained for immigration violations. She was then deported to the U.S. on July 2 and booked into the Gulf Coast Violent Offender Task Force at the George Bush Intercontinental Houston Airport. She was initially detained at the Harris County Detention Center in Houston.

On July 5, APD extradited Armstrong from the Harris County Detention Center to the Travis County Detention Center in Austin, where she was formally charged with first-degree murder felony in connection with Wilson's death.

"We also want to remember the victims in this case and hope this is an early step in closure for Wilson's family," Fila said.

After Armstrong's arrest, Wilson's family released a statement saying they were "relieved that this uncertain phase has passed and believe that justice will prevail."

In the search for Armstrong, Fila noted that the U.S. Marshals Service deployed two marshals to the U.S. Embassy in Costa Rica to assist the State Department and foreign officials with information regarding Armstrong's possible location.

"From what we know, she was very involved in the yoga community. That was her practice. And when we were able to contact foreign officials in Costa Rica, they had context in the local community and knew the area better than anyone else. I focused on where she got on the bus from the coast, which is two hours away from the San Jose airport in Costa Rica. It's a two-hour bus ride from the San Jose airport in Costa Rica to the coast. They narrowed down the whereabouts of Caitlin Armstrong," Fila said.

In the course of their investigation, they learned that Armstrong had traveled under different aliases to several destinations, including San Jose, where she first landed at the airport. She also went to Jaco Beach and Santa Teresa Beach, where authorities arrested her at Don John's Lodge Hostel.

"It was found that Armstrong used different names, aliases, and went by the aliases Beth Martin, Liz Martin, and Ali Martin, which she advised uniformed officers at Don John's Hostel in Costa Rica. Armstrong had been using these names at the yoga studio and other accommodations since her arrival in Costa Rica on May 18," Fila said.

"The officers involved in the investigation used old-fashioned law enforcement techniques, going door to door, conducting numerous interviews, going from one yoga facility to another, and making contact with the accommodations she left behind. This led to Armstrong being detained by authorities at Don John's hostel in Santa Teresa Beach, Costa Rica.

Fila confirmed that after her arrest, two passports were found in a locker at the hostel. Witnesses told Inside Edition that one belonged to Armstrong and the other to a family member.

Fila did not comment on the name of the owner of the passports, as the investigation is ongoing. However, he did confirm that authorities are investigating how Armstrong obtained the passports. According to Fila, the passport is currently in the possession of authorities as evidence in the murder and fugitive investigation.

"That is an ongoing investigation. We have forwarded that information to the U.S. Attorney's offices in Austin and New Jersey," he said.

A $6,350 receipt for cosmetic surgery was also found in the locker under a different name. However, because of the different name, Fila could not confirm that this was the cosmetic surgery Armstrong had undergone. He confirmed that she had cut her hair, dyed it dark brown, and placed a plaster over her nose to alter her appearance.

"At the time the foreign officials arrested and detained Caitlin Armstrong, they believed that she did not have a key to the locker box in which she kept her belongings and that the owner at the time was not in a position to unlock that lock box. She was therefore taken into custody and transported from the location. Later, a news specializing station ("Inside Edition") contacted the owner of that hostel, and I believe he voluntarily retrieved his passport documents. Those receipts, as you know, were posted by one of the media outlets regarding plastic surgery. All those documents were turned over to the authorities and are now in evidence," Fila said.

Stan Seto, Assistant Special Agent in Charge of the Homeland Security Investigative Service, congratulated APD and the U.S. Marshals Service for leading the 43-day fugitive search to apprehend Armstrong. [18][19] "I just wanted to take the opportunity to recognize and speak to the tenacity of the U.S. Marshals Service and its task force members and the arrest of this international fugitive. Our sole responsibility as law enforcement partners is to fight international crime, both in the United States and abroad. So we are very grateful that some of our agents stationed overseas in Costa Rica supported the efforts of the (U.S.) Marshals in Costa Rica to locate and comb through leads," Seto said.

"In short, the success of this operation sends a clear message that criminals are not beyond the reach of the law, no matter where they commit their crimes or where they flee. We will leverage every resource partnership we have to ensure that you will be brought to justice."

Based on legal documents, Cycling News has compiled a timeline of how authorities believe this crime unfolded. Cycling News will provide additional information as more information becomes available from authorities through this investigation.