Iran-contra figure and biotechnology executive Richard V. Secord, under scrutiny from a federal grand jury, has repurchased more than 100,000 shares of stock he sold just before its value plunged 63 percent, according to a federal filing.

The purchase of stock in Computerized Thermal Imaging Inc. reversed Secord's original sale but may have run afoul of another federal rule that forbids executives from profiting from the sale of company shares within a six-month period, securities lawyers said yesterday. The sale and repurchase left Secord, the chief executive of CTI, with a profit of $98,734, the filing said.

A grand jury in New York last week began investigating Secord's $127,058 stock sale, focusing on whether he possessed insider information about a federal advisory panel's decision on one of his company's products, people familiar with the matter said. He repurchased the shares Dec. 13, according to a Securities and Exchange Commission filing.

"It sounds like someone who's trying to say, 'This is a do-over, I'm taking it all back,' " said Columbia Law School professor John C. Coffee Jr. "But this was not a wash economically; Secord made a very large profit."

The purchase is the latest twist in a case that has puzzled securities experts and returned investors' attention to an issue -- ill-timed CEO stock sales -- that many thought was moot after ImClone Systems Inc. chief executive Samuel D. Waksal pleaded guilty to insider trading in October. It has also thrust Secord, who served as deputy assistant secretary of defense under President Ronald Reagan and who pleaded guilty to lying to Congress about his role in the Iran-contra affair, back into the public spotlight.

Neither Secord nor his attorney, Carl F. Schoeppl, was available for comment yesterday. A spokesman for the SEC also declined to comment.

Secord, 70, a retired Air Force general who has headed Lake Oswego, Ore.-based CTI since 2000, completed the sale of 111,300 shares of company stock last week at an average price of $1.14 per share. The sale accounted for 27 percent of his holdings, according to SEC documents.

The last of three transactions occurred Dec. 10, hours before a Food and Drug Administration advisory panel voted against recommending approval of CTI's breast cancer detection system. After the 4 to 3 decision was announced, CTI's stock price collapsed, closing at 39 cents a share. Two days later, federal agents served Secord with a subpoena as he concluded a shareholder meeting at the American Stock Exchange headquarters in New York, a source familiar with the matter said.

Secord purchased the 111,300 shares Tuesday for an average of 25.5 cents a share. According to SEC filings, the sale left him a profit of $98,734.

But the sale and repurchase is a possible violation of SEC Rule 16(b), which bans insiders from profiting from either selling and buying, or buying and selling, stock within six months, said Samuel J. Winer, head of the SEC enforcement practice at law firm Foley & Lardner in Washington. Under the "short swing profit" rule, executives who carry out such sales must hand over any profit to the company.

"The law doesn't require a lot of judgment," said Winer, a former SEC enforcement officer. "The sale can be absolutely innocent, but the profit still has to be returned."

The SEC rarely prosecutes individuals who violate the statute, securities experts said. Repayment alone typically satisfies the agency. But even if Secord pays CTI $98,734, the U.S. attorney in Manhattan could prosecute the executive for alleged insider trading.

"Paying the money back to the company does not help the individual investor at the other side of his stock trade," Winer said.

Coffee said that returning the money "neither causes Secord to surrender any gain or avert any loss."

"In fact, he has restored his original share ownership; that is what any inside trader would like to do," he said.

Company officials declined to talk about Secord's stock sales or whether they will seek to reclaim the profit gained from them, said spokeswoman Kristy Cory. CTI's stock has fallen 80 percent since the vote by the FDA advisory panel, closing yesterday at 23 cents.

The panel's vote was a stinging disappointment for the cash-strapped CTI, which has pinned its plans for survival on the screening device. The system uses infrared technology to differentiate between malignant and benign tumors. But FDA panel members said in interviews that the company provided insufficient data to establish the screener's effectiveness and safety.

Shareholders have filed several lawsuits accusing CTI's former president and chief operating officer, David A. Packer, of misleading investors about possible FDA approval of the device to inflate the company's stock price. During the time named in the lawsuits -- Oct. 11, 1999, to Dec. 21, 2001 -- CTI stock fell 91 percent, to $1.68.

In its annual report for the year that ended June 30, CTI's outside auditor, Deloitte & Touche, warned that the company's recurring losses -- it lost $21.7 million during that period -- possible FDA rejection of the scanning device, and its lawsuit liability "raise substantial doubt about the company's ability to continue as a going concern."

Richard V. Secord, who was in the spotlight during the Iran-contra affair, is under investigation for his recent stock transactions as CEO of Computerized Thermal Imaging Inc.