A South American businessman said to have led a violent paramilitary organization in Guyana is likely to spend the next 15 years in a U.S. prison.

Shaheed "Roger" Khan pleaded guilty Monday to cocaine trafficking, weapons charges and witness tampering as part of a deal with federal prosecutors in Brooklyn.

Federal authorities said Khan imported major amounts of cocaine into the U.S. while leading an armed group that has been accused in as many as 200 killings in Guyana. He was arrested in Suriname and deported to the U.S. in 2006 to face drug charges.

While he was awaiting trial, Khan and one of his New York lawyers were charged with conspiring to silence witnesses in the case.

Prosecutors said federal agents secretly recorded the attorney, Robert Simels, speaking to one of Khan's associates about using bribes or violence to keep people quiet about his crimes.

"Any witness you can eliminate is a good thing," Simels said, according to prosecutors.

Simels, a seasoned defense attorney whose clients have included "Goodfellas" mobster Henry Hill, is charged with witness tampering and obstruction of justice. His attorney, Gerald Shargel, said Tuesday that Khan's guilty plea will have no effect on the case.

He said a trial will prove that Simels' conduct was "nothing more than a lawful effort to vigorously defend his client."

Khan's attorney did not immediately return a phone call Tuesday.

The plea bargain calls for Khan to serve 15 years in prison in exchange for resolving the drug trafficking charges, the witness tampering case, and a federal weapons charge dating from when Khan lived in Vermont in the 1990s.

The plea bargain doesn't involve any of the alleged slayings in Guyana.

Khan became one of Guyana's richest businessmen after moving there in 1993. He controlled businesses that ranged from housing developments and discos to carpet cleaning.

Copyright 2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.