NEW YORK (CNN/Money) - Federal lawmakers have sent the Martha Stewart inquiry to the Justice Department after a summer spent probing the home design celebrity's controversial sale of ImClone Systems shares just before they tumbled.

The referral means that a congressional panel won't call Stewart to answer questions about a matter that has frustrated investigators and sent shares of Stewart's company sliding.

"It's properly a matter for the Justice Department to pursue," concluded Congressman Billy Tauzin, R-La., who chairs the House Energy and Commerce Committee, during a Tuesday afternoon press conference. "We've taken it as far as we can."

Stewart's attorneys welcomed the move, saying it will take politics out of a case that Congress was unqualified to tackle.

"I strongly disagree with the analysis of the committee and its staff, but am pleased that the matter will now be exclusively in the hands of professional law enforcement authorities who are trained to conduct a responsible and thorough investigation," said a statement from Robert Morvillo, one of Stewart's lawyers.

Tauzin said sending the case to federal prosecutors will not end his panel's look into the disappointment surrounding ImClone Systems' highly touted cancer drug.

But the move will halt what some panel members called frustration with Stewart's level of cooperation with their requests.

In a letter to John Ashcroft, the U.S. attorney general, Tauzin and the panel asked the department to examine whether Stewart "knowingly caused materially false representations" to the committee.

"As members of Congress, we believe it is our obligation to forward specific and credible information in our possession that could suggest a federal crime has been committed," Tauzin wrote.

Tuesday's news douses a potential media inferno: subpoenaing Stewart to publicly answer questions about whether she profited from inside information last December.

Still, James Greenwood, R-Pa., who chairs an investigations subcommittee, said Stewart's lawyers indicated that the CEO of Martha Stewart Living Omnimedia (MSO: Research, Estimates), a publishing and home-design company, would likely exercise her Fifth Amendment right and not testify if subpoenaed.

Now, Justice Department investigators may take over a matter that Ken Johnson, a Tauzin spokesman, has said is rife with inconsistencies.

A spokesperson for Martha Stewart Living declined comment Tuesday.

Stewart sold 3,928 shares of ImClone Systems on Dec. 27. The sale came a day before the Food and Drug Administration's refusal to consider an application for Erbitux, ImClone's promising cancer drug, sent ImClone (IMCL: Research, Estimates) shares tumbling.

Stewart has denied having advance knowledge of the news, saying she had a long-standing agreement with her broker to sell ImClone shares when they fell below $60.

But congressional investigators said the accounts from Stewart, her brokers and Sam Waksal, the former ImClone CEO and a friend of Stewart's, don't add up. Waksal has pleaded not guilty to charges that he tried to sell ImClone shares and tipped off family members ahead of the FDA news.

Tauzin wrote to Ashcroft that the committee "has been prevented from attempting to resolve many of the discrepancies, ambiguities, and suspicious communications outlined in this letter."

But saying they were confident of Stewart's exoneration, Stewart's lawyers criticized the House panel's handling of the matter, saying the attorneys fully cooperated by turning over "more than 1,500 pages of documents."

"During the past several months, Ms. Stewart has been the subject of numerous leaks, unfair innuendo and thunderous headlines, none of which merit reply," the attorneys said. "We do not see how anyone, lacking full information and access to all relevant parties, could reach a fair, final conclusion."

The panel's focus on Stewart, beginning in June, has sent shares of Martha Stewart Living tumbling more than 50 percent by raising questions about a company whose image is closely entwined with its CEO. But shares of Martha Stewart Living jumped $1.30 to $9.05 following the referral news Tuesday.

In turning over the matter, the House panel said it will send hundreds of pages of documents and e-mails to federal prosecutors. But it's not clear what will be done with them. The Justice Department declined to comment on the referral.