Tania Valdes says she found out her son was being held hostage after receiving a call from an anonymous group asking for money in January.

Her son, Osman Khan, a 24-year-old American citizen, had been working remotely from the small Colombian city of Bucaramanga for months after graduating from the University of Central Florida. Around the holidays, Khan informed his sister that he had begun dating a girl there and that the relationship was becoming serious. But he didn’t say anything about crossing the Colombian border to see her family in Venezuela.

Valdes claims that on the night of January 17, an anonymous group sent her a video of Khan being apprehended in a mundane office. They sent her voice messages of Khan pleading for help.

The group initially requested $1,200 from Valdes in order to secure Khan’s release. On the advice of friends and family, she bargained them down to $600 to send a message to his kidnappers that they couldn’t ask for anything more. She made the transfer. They still demanded more.

Valdes made the decision to act while huddled with family in her Winter Garden home. “One of the phone numbers that called me had a picture on the profile,” Valdes told McClatchy, revealing Khan’s story for the first time publicly. “My family and I started looking into things on our own. In Venezuela, we began browsing social media, looking through pictures and searching for names.”

Khan’s family pieced together that his captors were members of the Venezuelan National Guard based on information obtained from their extortionists’ Whatsapp and Zelle accounts. She confronted them with what she had discovered on January 18. After two agonizing days of silence, she learned that Khan had been transferred to the DGCIM, Venezuela’s military intelligence force.

Khan is one of more than a dozen Americans detained in Venezuela by Nicolás Maduro’s government. This number has grown in the last year, and US officials are concerned that Caracas is using increasingly aggressive tactics to lure and entrap US citizens at its borders, extort their families on the false promise of their return, and use them as bargaining chips with Washington.

While US officials lack concrete evidence, some cases appear to involve sophisticated honey pot operations in Colombia to seduce American tourists — an espionage tactic more commonly reserved for targeting foreign spies and assets rather than average Americans.

Khan has been waterboarded, electrocuted, starved for five days, forced to stand for hours, and strapped down against his will in the eight months since his detention, according to his family.

In March, Roger Carstens, the United States’ special envoy for hostage affairs, was able to secure the release of two Americans held in Venezuela. He returned from his most recent trip to Caracas in June with Maduro’s proposal for a prisoner swap, which has been sitting at the White House ever since.

According to a source familiar with Venezuelan prisoner negotiations, Maduro’s general offer came in two parts. Venezuela could either release all Americans in its custody in exchange for all Venezuelans detained in the US, or the two countries could agree on a partial swap with fewer prisoners released.

State Department officials declined to comment for this report but did not dispute Osman’s family’s account of events.

Khan told his mother that his girlfriend, a Venezuelan national who worked at a nightclub in Colombia, first mentioned a trip to Venezuela when her father paid her a visit on New Year’s Eve. Khan sought advice from her half-brother, a member of the Venezuelan National Guard, after expressing concern about the trip’s safety.

Valdes does not believe Khan’s girlfriend was involved in an entrapment scheme — the girlfriend still visits Khan on Saturdays to bring him food and books — but she believes her half-brother was. “I think her half-brother sold my son,” she explained.

In the midst of their country’s ongoing economic and political crisis, millions of Venezuelans have sought refuge in Colombia. Khan’s girlfriend was not arrested upon her arrival in Venezuela alongside him, and she has not returned to Colombia.