The State Department acknowledged it is investigating alleged "improprieties" regarding a consular official who until recently was posted to Guyana, following reports he was trading visas for money and possibly sex.
The department said in a statement it was "aware" of the allegations, without going into detail.
"The department takes all allegations of misconduct by employees seriously," a spokeswoman said in an email.
"We are reviewing the matter thoroughly. If the allegations are substantiated, we will work with the relevant authorities to hold anyone involved accountable."
The department would not identify the individual, though media reports in Guyana have.
Mark Benschop, publisher of the Guyana Observer, told FoxNews.com that his organization's investigation shows that the U.S. employee was in touch with "questionable characters" ranging from "unscrupulous businessmen" to people in the drug trade.
Benschop said the officer was either part of a scam or "manipulated" into getting involved.
He said one source close to the individual explicitly claimed he was trading visas for money -- Benschop said rates were said to be as high as $40,000, though the officer presumably would have split that money with others.
The Guyana Observer also reported last week on allegations that the official issued "dozens of visas" to Guyanese women for sex.
Benschop told FoxNews.com that it might not have been a quid pro quo with the women -- "not necessarily 'have sex with me and I'll give you a visa'" -- but it came close.
He also said the officer was removed from his South American post and sent back to Virginia recently, well before his assignment was scheduled to end in September.
AFP previously cited "government sources in Guyana" as saying the official used a popular Georgetown, Guyana, restaurant and bar to conduct his business. Another local media report claimed the alleged visa scam may have been going on for months.
The allegations conjure bad memories in Guyana, coming 13 years after a former U.S. embassy official -- Thomas Carroll -- was arrested, and ultimately imprisoned, on charges of selling U.S. visas for thousands of dollars apiece.
Benschop explained that some in Guyana use the services of what are known as "backtrackers" -- black-market operatives who charge money for people having difficulty obtaining a visa. They then coordinate with "corrupt" embassy officials, with whom they split the money, to facilitate the issuance of the visas.
Benschop said the individual in question had been seen on trips with "known backtrackers."