ImClone Systems Inc. founder Samuel D. Waksal, who is already facing years in prison for securities fraud, pleaded guilty today to conspiracy and wire fraud for plotting with a Manhattan gallery owner to avoid paying $1.2 million in sales tax on nine paintings he bought for $15 million.

The plea makes Waksal the second New York tycoon to face criminal charges of pretending to ship fine art out of state to avoid the 8.25 percent sales tax. Former Tyco International Ltd. chief executive L. Dennis Kozlowski is facing state tax-evasion charges for allegedly claiming falsely that he bought paintings for the company's New Hampshire headquarters.

The Waksal charges arose from an independent FBI investigation of a different -- and still unnamed -- dealer than the one who figured in the Kozlowski case, and more prosecutions may be coming, said Jim Comey, the U.S. attorney for Manhattan. "If you are someone who is engaged in similar wrongdoing, come see us before we come see you," he said. "We won't be coming to admire your art. . . . Tax fraud is always a serious crime."

Today's guilty plea before U.S. District Judge William H. Pauley III helps resolve an impasse that developed in October when Waksal, 55, pleaded guilty to six of the 13 charges he faced in connection with insider sales of ImClone stock shortly before the company announced that the Food and Drug Administration was rejecting an application for its cancer drug.

Waksal's father, Jack, daughter Aliza and friend Martha Stewart all sold shares in December 2001. All three are under investigation. Samuel Waksal has denied tipping off his father and Stewart, and he said his daughter did not know why he wanted her to sell.

But prosecutors said they wanted his sentence to reflect that his relatives pocketed $10 million in stock sales.

Prosecutors and Waksal's attorneys said today's plea may make the remaining seven counts irrelevant because of the way the federal sentencing guidelines are calculated. Waksal, 55, is facing six to eight years in prison, whether or not the additional insider-trading charges are included. Both sides still have the option of asking Pauley to move above or below that range.

Waksal has not secured a formal plea agreement, but Assistant U.S. Attorney Michael Schachter said the government intends to drop the remaining charges if the May 29 sentencing comes out as prosecutors expect.

Waksal said in a statement: "Only two things are important to me at this point -- my family and getting our cancer drug approved. Beyond that, I simply look forward to the day when I can put all of this behind me and move on with my life."

ImClone stock closed at $14.35 today on the Nasdaq Stock Market, up $1.02 a share, or 7.7 percent. The stock is still down sharply from December 2001, when it was above $70.

Waksal attorney Mark Pomerantz said his client has been working with prosecutors who are investigating other sales of ImClone stock. "Dr. Waksal met with government representatives . . . to make the government aware of other trading by others," Pomerantz said. "I am not alluding to Martha Stewart," he added.

Comey declined to comment on other targets, including Waksal's father and daughter, although he said the ImClone investigation is continuing. "We have wrapped it up with Mr. Waksal," he said.

At today's hearing, Waksal told the judge that in 2000 and 2001 he and an art dealer arranged to ship some of the nine paintings he purchased to ImClone's Somerville, N.J., manufacturing plant and then back to New York to avoid paying sales tax. Other paintings were shipped directly to Waksal's Manhattan loft, even though the sales documents said they had gone to New Jersey, according to documents filed in U.S. District Court in Manhattan.

The art included paintings ranging in price from a $60,000 work by Francesco Clemente to pieces worth $3 million or more by Francis Bacon, Mark Rothko and Franz Kline.

"At all times, I knew that avoiding payment of New York sales tax was wrong," Waksal told the judge. Pomerantz said his client was "not the architect of the scheme" and began in October repaying what he owes through New York's tax amnesty program.

Although Waksal evaded state taxes, he was charged with federal wire fraud and conspiracy because he wired the money for the paintings from banks in North Carolina, California and the Netherlands to the gallery's accounts in New York. Each charge carries a penalty of up to five years in prison.

Kevin Donovan, assistant director in charge of the New York office of the FBI, announces that Samuel D. Waksal admitted that he avoided paying sales taxes on $15 million in art purchases, including the paintings depicted at left. At right is U.S. Attorney Jim Comey. Waksal leaves federal court in New York after pleading guilty to conspiracy and wire fraud.