* Newspapers report no evidence wife knew of fraud
* FBI will investigate firm's premises until July 2010 (Adds FBI on firm's premises until next year)
NEW YORK, July 1 (Reuters) - Ruth Madoff, the wife of swindler Bernard Madoff, will not face criminal charges because of lack of evidence of her knowledge or involvement in his multibillion dollar fraud, two newspapers reported on Wednesday.
The New York Post and the Wall Street Journal each cited two sources familiar with the probe by federal investigators, which continues after Madoff, 71, was sentenced to 150 years in prison on Monday after pleading guilty in March.
A spokeswoman for prosecutors declined comment and a lawyer for Ruth Madoff, 68, could not be reached for comment.
A law enforcement source said that 10 or more people closely associated with Madoff and his firm could face criminal charges over the next few months or beyond, but declined to discuss who is the focus of the probe [ID: nN30439889].
Federal investigators were "closer to the beginning than the end" of the investigation into Wall Street's biggest investment fraud, the law enforcement source said.
Court documents filed on Wednesday by the trustee winding down Bernard L. Madoff Investment Securities LLC said FBI agents will be working on the 17th floor of the defunct firm's Manhattan headquarters for at least one more year.
"The FBI has advised me that they will require access to the space until, at least, approximately July of 2010," court-appointed trustee Irving Picard said.
The filing was made in connection with leases on three floors of the office tower known as the Lipstick building.
Madoff became a symbol of greed and lax financial regulation after admitting to orchestrating a classic Ponzi scheme in which early investors are paid with money of new clients. Prosecutors said the scheme may have pulled in as much as $65 billion over 20 years [ID: nN01502472].
Under an agreement with prosecutors made public on Friday night, Ruth Madoff agreed to forfeit any claims to $80 million in assets and was left with $2.5 million in cash. The deal does not rule out future criminal charges or civil charges by regulators.
Some of the defrauded investors have publicly stated their suspicions about the disgraced financier's wife of 45 years. She issued a statement after his sentencing saying she was sympathetic to those left in financial ruin.
"Like everyone else, I feel betrayed and confused," her statement said.
"To say that I feel devastated for the many whom my husband has destroyed is truly inadequate," she said. (Reporting by Grant McCool and Martha Graybow)