The suit, filed April 11 in US District Court in Houston, alleges that Hancock made the investments based on false and misleading information provided by Enron and endorsed by its auditors.

"We are alleging that Enron's officers and directors were directly complicit in the fraud perpetrated against us," Hancock chief executive David D'Alessandro said in a statement. "We have a fiduciary responsibility to our shareholders and intend to pursue this action very aggressively." Boston-based Hancock is the latest in a string of insurers and large investors to sue Enron executives and directors, and Andersen. Karen Denne, spokeswoman for the bankrupt energy trading company, declined to comment on the lawsuit, as did W. Neil Eggleston, a lawyer representing Enron's independent directors.

Hancock filed its suit as a class action that could include other investors who bought nonpublicly traded Enron securities between Oct. 19, 1998, and Nov. 27, 2001. The insurer named its own units, Investors Partner Life Insurance Co., John Hancock Life Insurance Co., and John Hancock Variable Life Insurance Co., as lead plaintiffs.

The suit filing comes on the heels of a large fourth-quarter write-down for Hancock. The company saw its quarterly net income plunge 55 percent from the same period a year ago, as it recognized losses on $98 million in underwater investments, most of them Enron bonds. Moody's Investors Service last week downgraded Hancock's debt ratings, citing the company's "significant investment concentration in lower-quality and less-liquid bonds and commercial mortgages."

In the case of the Enron investments, Hancock said in its complaint that Enron had presented itself as a healthy company when Hancock had purchased its bonds. When Enron restated its earnings in late 2001, its bond ratings fell to junk level, Hancock said. The values of other Enron securities and debt obligations "dropped precipitously after the disclosures of these restatements and after subsequent disclosures regarding improper accounting and self-dealing by Enron officers."

-- Beth Healy