Energy and Commerce Committee Chairman Rep. Billy Tauzin, R-La., said Thursday he has made a final decision regarding Martha Stewart, who is being investigated for her sale of stock in ImClone.

"We have reached the end of the road," he said, referring to fruitless attempts to get Stewart to supply documents and come before the committee to talk about the insider trading scandal at biotech firm ImClone.

Tauzin said he has made up his mind on what to do with Stewart -- whether the committee will subpoena the home fashion queen or refer the case to the Justice Department -- and will announce his decision by Tuesday.

The committee's oversight panel is investigating ImClone executives' stock sell-off following unofficial word that the Food and Drug Administration was going to reject Erbitux, its star-making cancer drug, earlier this year.

Stewart has been asked by the committee to testify and hand over files related to the sale of nearly $4,000 worth of her shares of company stock, which took place a day before the stock plunged.

The chairman has expressed frustration before that Stewart and ImClone CEO Sam Waksal lied to the committee in earlier interviews. Waksal was indicted last month on federal fraud and obstruction of justice charges. Waksal's advice to the home fashion designer, whom he admits is a friend, is being called into question.

If Stewart acted on a tip from Waksal, she could be charged with insider trading. If she lied when she said in preliminary interviews with the subcommittee that her selling of the shares weren't connected with any tip, she could be bagged for obstruction of justice.

So far, Stewart, who heads Martha Stewart Living Omnimedia Inc., has answered the subcommittee's calls, while her lawyers say they are doing their best to comply with requests for her records. Meanwhile, Tauzin's office said phone records the committee has obtained contradict Waksal's and Stewart's assertions that they did not talk to each other in the weeks immediately before her stock sale.

Sources also told Fox News Thursday that committee members believe they have been lied to and that "someone" has conspired to obstruct their investigation.

Tauzin's office said it was not ruling out a formal report to the Justice Department.

Fox News' Kelley Beaucar Vlahos and The Associated Press Contributed to this report