"We take these things very seriously," said FBI spokesman Bill Carter, who added, "we have no specific and credible information about a credible threat to Goldman Sachs other than these letters."

The letters were postmarked late June from New York and were handwritten in red ink on loose-leaf paper.

"We are working closely with the law enforcement authorities, who tell us they don't believe the threat to be very credible," Goldman Sachs said in a statement today. "We have a broad range of security measures in place to counter all likely threats and we're monitoring the situation closely."

The Fort Wayne Journal Gazette received the letter Monday, said Bobby Wells, the newspaper's administrative assistant, and the FBI and local police department have since picked up the letter.

The Star-Ledger reported that it received one of the letters, postmarked June 27. The letter was addressed to the news department and was turned over to the FBI, according to the newspaper.

Goldman is a powerhouse in investment banking, with $37 billion in revenue last year and a profit of $9.5 billion. It hands out the biggest paychecks on Wall Street, averaging $623,418 per employee last year with individual rainmakers raking in up to $50 million, according to U.S. regulatory filings.

Goldman Sachs sent the following internal memo to its employees:

"The firm is aware that a number of local newspapers in a few places in the U.S. have received anonymous letters threatening the firm. We take any threat to the safety of our people and our business very seriously. The Office of Global Security has consulted the FBI and other relevant authorities. Authorities have informed us that they believe the threat to be of low credibility. Nevertheless, they have mounted an active investigation to try to determine the source of the letters. We have a broad range of security measures in place to counter all likely threats and we continue to monitor this situation closely. We do not view this situation as a cause for concern."

A source at Goldman who asked not to be named said that the firm didn't think the letters were credible and that officials were satisfied with the many security provisions in place, especially in New York.