Wife of Ex-Enron Chief Stock Sale Probed  HOUSTON (Reuters) - Federal prosecutors are investigating  whether the wife of former Enron Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=ENRNQ.PK target=/stocks/quickinfo/fullquote"&gt;ENRNQ.PK&lt;/A&gt; Chairman Ken  Lay illegally sold shares in the company just before it went  bankrupt, a lawyer for Lay said on Wednesday.