WASHINGTON (Reuters) -

New evidence shows Enron Corp. was still manipulating energy markets a year after the company claims it stopped, a Democratic senator said on Thursday, asking that lawmakers haul the company back to Capitol Hill to explain the discrepancy.

Internal documents and audiotapes revealed that Enron continued manipulative trading practices virtually until its bankruptcy in December 2001 although executives told Congress in sworn testimony that those kinds of strategies stopped in December 2000, said Sen. Maria Cantwell of Washington state.

Cantwell lives in a county where the local utility is battling Enron in court. She asked the Senate Commerce and the Senate Energy and Natural Resources committees to hold hearings on the new evidence, obtained through legal and regulatory proceedings.

"We now have evidence that Enron continued to manipulate the markets, beyond when they notified traders internally that this was illegal and should stop," she told reporters. "Why is there this discrepancy?"

Cantwell said the new evidence showed Enron kept at least five different sets of books, and also provided a "snapshot" of its unfair profits from energy manipulation schemes, which she said were conservatively estimated at $1.1 billion.

Regulators at the Federal Energy Regulatory Commission are "sitting on their hands," she said, so Congress should investigate. Last week, FERC agreed to review the new evidence to see if it could affect its existing cases against Enron.

A Senate Energy Committee spokeswoman said Enron hearings already had been held in both chambers and "this ground has been thoroughly plowed by all branches of government."

"We are continuing to cooperate fully with all investigations," Enron spokeswoman Karen Denne said, but declined further comment.

'GET SHORTY'

Enron lawyers testified under oath to a Senate Commerce subcommittee in May 2002 that in December 2000 the company had put a stop to deceptive trading practices infamously dubbed "Ricochet," "Fat Boy," "Get Shorty" and other nicknames, which involved shifting power around between states.

But internal "reconciliation sheets" kept by Enron show the manipulation continued for 191 days in 2001, Cantwell said. She released copies of one such sheet from Dec. 2, 2001, on which someone had scrawled, "variances due to load shift." The documents were obtained through the discovery process in FERC proceedings, she said.    

"I think this is about a 10-million-dollar deal," one voice says on the tape. "Profit? Oh!" exclaims the other.

Snohomish's utility obtained the tapes from the Justice Department, which seized them as part of a criminal probe.

The revelations are important to ratepayers throughout the West, where Enron is suing several utilities to collect on broken contracts, Cantwell said. If Enron wins its $122 million lawsuit against Snohomish County's utility, the average ratepayer there will be forced to pay $420, she said.

"I think it's ridiculous that they expect to get paid," she said. "What kind of message are we sending to markets of the future if we are saying fraudulent contracts should stand?"

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