Carla Stefaniak, from Florida, was visiting Costa Rica to celebrate her 36th birthday.
She went missing on November 27 — after texting a relative that the area where she was staying was "pretty sketchy" — and never boarded her return flight the following day.
Bismarck Espinosa Martinez, 32, a Nicaraguan security guard at the apartment complex in Escazu, a suburb of the capital San Jose, has been arrested on suspicion of her murder. Her blood was reportedly found in his nearby apartment.
Espinosa Martinez, an illegal immigrant, is believed to have lived in Costa Rica since June.
Tens of thousands of Nicaraguans live and work in neighbouring Costa Rica, which has a thriving tourist industry.
Eric Horvath and his girlfriend, from Chicago, stayed in the same apartment as Carla in July after booking it through Airbnb.
"When I clicked the link to an article and discovered it was the exact same place I was I was very freaked out. A million things went through my mind such as ‘that could have been me or my girlfriend'," Mr. Horvath told Sputnik.
But he said he was "extremely surprised" and did not believe Costa Rica was a dangerous country.
"I came back from that trip with rave reviews. Not once did I feel in danger. The host and owner was incredibly hospitable. Bismarck, the suspect who has been charged, was so nice to us, always with a smile on his face," Mr. Horvath told Sputnik.
"I'm going to miss the place," Ms. Stefaniak wrote, along with a selfie in her bikini, on Instagram on November 25.
Two days later her sister-in-law April Burton flew back to Florida.
Ms. Stefaniak was due to fly back the following day, which was her birthday.
She loved to travel and had been to Mexico, Iceland and Switzerland as well as several places in the United States.
Mr. Horvath said travelling alone had its dangers, especially for a woman.
"I'd say it's best to not travel alone regardless of where you are at. I don't think this should be a banner for ‘do not travel to Costa Rica because you will get killed.' Bad people live everywhere," Mr. Horvath told Sputnik.
He said he never felt unsafe in Costa Rica and was never taken advantage of by the locals, despite his inability to speak Spanish.
But Ms. Stefaniak, who was born in Venezuela, spoke Spanish fluently.
Walter Espinoza, director of Costa Rica's Judicial Investigation Department, has said the killing may have been sexually motivated.
Ms. Stefaniak's body was found wrapped in plastic and dumped about 1,000 feet from the apartment. She had been stabbed and her neck had been broken.
According to NBC News on Ms. Stefaniak's final day in the apartment it was stormy and the power went out at one point. During a Facetime call with a friend she mentioned that she had asked a security guard to buy her some water.
Airbnb removed the apartment complex from its site this week and said it had offered its condolences to the family.