The family of Carla Stefaniak, the Florida woman who disappeared last week during a birthday trip to Costa Rica, confirmed that a body found near her rented Airbnb is hers.

Costa Rican authorities said Monday that a body partially buried in plastic bags was found about 300 yards from Villa le Mas in San Antonio de Escazú, west of San José.

Carla Stefaniak via Facebook

Stefaniak's brother and father had traveled to the country to view the body. Her brother, Mario Caicedo, confirmed the death to NBC News on Wednesday morning, saying that they were able to see the remains Tuesday night.

Walter Espinoza, director general of the Organismo de Investigación Judicial, the investigative agency in the case, said in a recorded press conference Wednesday that the motive appears to be sexual.

The head of the medicine unit for the investigative agency said Stefaniak's body was found half-naked.

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Costa Rican authorities on Monday arrested Bismarck Espinosa Martinez, 32, a security guard at the Airbnb complex where Stefaniak was staying in connection with her disappearnce.

Espinoza said at Wednesday's investigators were looking into the possibility of there being more suspects, and said people close to Martinez were brought in for questioning.

It's not clear if Martinez has been charged with a crime.

Stefaniak was last heard from on Nov. 27, after dropping her sister-in-law off at the airport after the two vacationed in Costa Rica to celebrate Stefaniak's 36th birthday. Stefaniak was supposed to catch a flight back home on Nov. 28.

Bismarck Espinosa Martinez, who had been staying in a room next to that of Carla Stefaniak, was arrested Monday night, Costa Rican police say. Costa Rica Office of Judicial Investigation

According to a timeline provided to NBC News, she spent her last night in the country touring the city with an Uber driver before heading back to her Airbnb. Stefaniak chatted with friends on WhatsApp and FaceTime, at one point saying her rental was "super sketchy" because the power had gone out during a rainstorm.

She had also told a friend that because of the storm she was thinking about asking the rental's security guards to buy her some water.

Airbnb said in a statement Tuesday that Villa Le Mas has been removed from their listings, and they continue to support the Stefaniak family.