MIAMI BEACH, Fla. -- Investigators identified a key figure they said was responsible for bomb threats and robbery attempts that wreaked havoc and shut down a major Miami Beach thoroughfare last March.

Federal authorities said Allan Guedes Sharif, 27, is a fugitive living in Portugal and the mastermind behind the Miami Beach chaos. But, they said, he has claimed citizenship in Portugal and remains out of reach for arrest, Local 10's Glenna Milberg reported.

A grand jury indictment unsealed Tuesday in Miami Federal Court accused Sharif of calling a bank teller via cell phone on the morning of March 27, and ordering her to give $20,000 to his accomplice waiting in the bank, or he would detonate a bomb.

Authorities arrested the accomplice waiting inside the bank, Paolo Manuel Da Silva Almeida. They evacuated surrounding buildings and locked down Arthur Godfrey Road for several hours as they searched for the culprit.

Sharif is also accused of making similar cellular telephone threats from Portugal to two other Miami Beach banks that day, threatening explosions and death if Almeida were not released.

Almeida has since pleaded guilty to conspiracy and fraud. His plea deal indicates he has agreed to provide information about Sharif, with whom he has admitted to partnering in past bank fraud and robbery. He is currently in federal prison in Miami, awaiting sentencing scheduled for Dec. 7. If convicted, he faces up to five years in prison.

Sharif, a U.S. citizen, fled to Portugal and requested citizenship there in 2005, after a New York grand jury indicted him on bank fraud charges. He is eligible for citizenship because his mother is Portuguese.

"We've used all appropriate diplomatic channels to make an arrest," said Alexander Acosta, U.S. Attorney for the Southern District of Florida.

Meanwhile, the FBI reports Sharif has continued a series of extortion attempts via cell phone to businesses in the United States. Authorities believe similar calls to more than two dozens business in 17 states can be traced to Sharif in Portugal.

Agents said one of those threatening calls, to a Wal-Mart in Rhode Island, resulted in employees there wiring $10,000 to an account in Portugal.

"These are extremely serious charges," said Acosta. "We're extremely concerned he continues to walk the streets of Portugal."