NEW YORK (CNN/Money) - Federal investigators are looking into whether Army Secretary Thomas E. White engaged in possible insider trading in the sale of Enron Corp. shares last year, persons familiar with the situation told CNN on Monday.

The Federal Bureau of Investigation and the Justice Department are investigating whether White was involved in any way with the use of insider information to trade Enron stock last year, the sources said.

White was required to sell his holdings after becoming Army secretary, and has said he lost money on the shares, which were sold over several months last year as their price was falling.

The Wall Street Journal reported Monday that investigators appear most concerned with White's calls and contacts last October, when he sold off half his holdings, about $3.08 million in stock, as Enron's financial condition worsened.

White has acknowledged discussing Enron's problems in many of those calls, but said he did so out of concern for friends at the now-bankrupt firm. He said he did not possess or act on any inside corporate information.

"I never sold any stock based on what anyone told me at Enron," White told reporters on March 27.

Senior DOJ officials, who have been poring over virtually every Enron-related document and record, including White's phone records, were drawn by the timing of White's stock sales and his contacts with Enron officials, the WSJ said.