CHICAGO (AP) — A former American diplomat was sentenced Thursday to 21 years in federal prison for selling visas at the US Embassy in Guyana and hiring “death squads” there to intimidate witnesses.

Thomas Carroll, 34, sold up to 800 visas allowing buyers to sneak into the United States, charging between $10,000 and $15,000 apiece, prosecutors said. They said Carroll shared some of the bribe money with confederates, but could have pocketed up to $4 million himself.

“He was extremely avaricious, very greedy,” said Assistant US Attorney Carolyn F McNiven, the chief prosecutor in the case.

Carroll pleaded guilty in April 2001 to conspiracy to sell visas, making bogus visas and in a bribery scheme that prosecutors said preyed on those desperate to leave the poverty-plagued South American country.

Prosecutors said Carroll preferred to use go-betweens to sell visas rather than deal with buyers directly. Co-defendant Halim Khan, a Guyanese national, also pleaded guilty and awaits sentencing.

Carroll, a 1989 graduate of Northwestern University’s Medill School of Journalism, stood grim-faced as US District Judge Blanche M Manning sentenced him to 262 months in federal prison.

His parents and his wife looked on mournfully while his infant daughter chattered in her stroller. With time off for good behaviour, Carroll could be released from federal prison in about 18 years.

Defence attorney Sheldon Nagelberg expressed “extreme disappointment” at the stiff sentence and told Manning he would appeal.

Manning found that Carroll’s activities caused a loss of confidence in government, a danger to the public welfare and a disruption of government activities.

The US Embassy in the Guyanese capital of Georgetown was ordered shut down by the ambassador for two days after the plot was discovered.

Another reason Manning cited for the stiff sentence was evidence that Carroll had intimidated witnesses by hiring sinister Guyanese death squads, described by McNiven as “quasi-paramilitary organisations”.

McNiven said the sentence was amply justified, given the amount of bribery, the weakening of US security and the violence involved in using death squads to cow into silence anyone who might turn him in.

“Our security is only as strong as its weakest link, and he was for a time one of its weakest links,” she said.

At the request of Senator Jesse Helms, a Republican from North Carolina, the government undertook a survey to determine how many of those who got into the country on visas sold by Carroll ended up committing crimes. Authorities said it was hard to get a firm figure because some bogus names were used.

But McNiven said at least 26 individuals were charged with crimes ranging from disorderly conduct to gang rape in the United States.

When Carroll was arrested by the State Department’s Diplomatic Security Service in March 2000, investigators seized dlrs 1 million in cash and 10 gold bars valued at $ 290,000, as well as an Irish passport.

Since his arrest, Carroll has been held in the government’s Metropolitan Correctional Centre in downtown Chicago.

He previously had been posted by the State Department to Taiwan and mainland China and was on his way to a new assignment in South Africa when he was caught.

Prosecutors said a man who succeeded Carroll as visa officer at the US Embassy in Georgetown, Guyana, agreed to pretend to be a corrupt diplomat in order to help in the investigation. They said he was threatened by a death squad but provided the evidence anyway.

A third man snared in the investigation, Hargobin Mortley, pleaded guilty in January 2001 and was sentenced to time served — nine months and 22 days.