NEW YORK (CNNfn) - Previously unreleased audio tapes and accounting records indicate that Enron manipulated the western electricity market 88 percent of the days between Jan. 1, 2000, and June 20, 2001, according to the Snohomish County Public Utility District in Washington state.

U.S. Sen. Maria Cantwell, D-Wash., and the Snohomish PUD said the tapes and documents show Enron "illegally obtained at least $1.1 billion in profits from western ratepayers."

One audio clip from Enron's West Coast trading desk recorded a trader giving instructions on how to profit from the power grid, utility officials said.

"If the line's not congested then I look to see if I can congest it," the unidentified Enron trader says on tape. "If you can congest it, that's a money maker no matter what because you're not losing any money to move it down the line. You're just making money."

Utilities repeatedly paid Enron to relieve congestion on the West Coast electricity grid.

CNNfn also has obtained some of Enron's accounting records, some of which refer to previously unreported market manipulation techniques called "sidewinder," "Russian roulette," "ping pong" and "donkey punch."

Enron is seeking $122 million from Snohomish PUD in a lawsuit filed after Snohomish terminated its power contract with Enron in November 2001.

"The lawsuit is a joke," said Al Aldrich, government affairs director for Snohomish PUD. "They went into bankruptcy two days after we terminated the contract so they couldn't have delivered on the contract anyway. It's outrageous."

Snohomish PUD is seeking refunds from Enron on behalf of the utility's customers.

New evidence is out that Enron traders manipulated the energy market to their advantage. CNNfn has obtained financial documents referring to previously unreported schemes. Play video (Real or Windows Media)

Cantwell called on the Federal Energy Regulatory Commission to investigate and take action against Enron.

An Enron representative said the company had not yet heard the tapes and thus had no comment.

Cantwell said she hand-delivered the documents and tapes to the Federal Energy Regulatory Commission and called on it to investigate and take action against Enron.

Kevin Kadden, FERC director of external affairs, said the commission is investigating. "We just dont know whether this contains any new information. I just handed it to the staff 18 minutes ago."