Two of the four Americans who authorities say were kidnapped in Mexico have been found dead, according to the Tamaulipas governor. The two surviving Americans are now in the care of the FBI and have returned to the United States, an official familiar with the investigation tells CNN.

One of the survivors was Latavia Washington McGee, a mother of six children who was traveling to Mexico for the second time for a medical procedure, her mother, Barbara Burgess, said.

She traveled to the country for surgery about two to three years ago, Burgess said. But this time, Burgess was informed by the FBI on Sunday that her daughter had been kidnapped and was in danger.

Receipts found in the group’s vehicle indicated the Americans were in Mexico for medical procedures, a US official with knowledge of the investigation told CNN.

Washington McGee’s close friend told CNN the trip was for a cosmetic surgery. The group booked a hotel in Brownsville and planned to drive into Matamoros for the surgery, according to the friend.

A day after the kidnapping, the friend became concerned and reached out to the doctor’s office for more information.

“When I reached out to the doctor’s office they told me that Latavia had reached out to them to ask them for directions because she was lost,” the friend said. “They sent me a screenshot of the messages and they said they sent her the address and asked her if she was using a GPS.”

The disappearance of the four was reported to Brownsville police on Saturday, according to a police report. The report states that Brownsville Police checked a local jail to make sure that no one in the party had been taken into custody, but no other action was taken.

Mexico has become a particularly popular destination for “medical tourism,” attracting travelers who may be seeking cheaper alternatives or medical treatments that are unapproved or unavailable in the US. But the CDC warns the growing trend can carry dangerous risks depending on the destination and facility, including infection and possible post-procedure complications.

Matamoros, however, is “not considered a primary medical travel destination,” said Josef Woodman, the company’s founder, “largely because there are no internationally accredited medical centers/speciality clinics there, or in the immediate region.”

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