The jury for his trial had been picked July 11.

"The government's case against this defendant is in a state of collapse," Barket wrote in a filing as recently as July 14 asking for the jury to be disbanded and the trial delayed. He said further investigation cast more doubt that McCrudden wrote the e-mail to Driscoll.

Legal Entanglements

McCrudden pleaded guilty because "he could not bear the pain and suffering that his family was going through," his sister Mary Eisenstein said after the hearing.

"This defendant crossed the line when he directly threatened to kill public officials who were working to keep our financial markets fair and open, and invited others to join him," U.S. Attorney Lynch said in an e-mailed statement. "He thought he could hide in the shadows of the Internet and disseminate his threats and instructions. He was wrong."

McCrudden's legal and regulatory entanglements began in 2000, when he was criminally charged with masking shortfalls in statements to his hedge-fund investors. The government alleged he included in his results money he expected to get from a lawsuit after Sumitomo Corp. was accused of manipulating the copper market.

In 2003, a federal jury in Central Islip acquitted McCrudden of 15 counts of mail fraud.

The National Futures Association in 2005 denied his registration application because of the alleged overstatements that resulted in that earlier criminal case. The CFTC and a federal appeals court upheld that decision.

Broker-Dealer

In October 2009, the Financial Industry Regulatory Authority Inc. ruled that McCrudden induced Hedge Fund Capital Partners LLC, a New York broker-dealer where he had worked, to file a form saying he left voluntarily when he was fired, which McCrudden denied. The National Adjudicatory Council, which hears appeals of Finra decisions, upheld that finding.