New York's Republican chairman called on state Attorney General Eliot Spitzer (search) to return a $25,000 campaign donation from a former top executive of a company his office had investigated.

The donation from Richard Ferrucci, a former senior vice president of Aon Corp (search)., came just three days before Spitzer's March 4 announcement of a settlement with the big insurance broker. It was part of Spitzer's investigation of anticompetitive practices in the insurance industry.

Spitzer, a Democrat who has gained wide attention for his investigations of various businesses, has said he will run for governor next year.

A spokesman for Aon, Al Orendorff, said there was no connection between the settlement and the donation, made 16 months after Ferrucci left the company.

Under the agreement, the nation's No. 2 insurance brokerage agreed to pay $190 million in restitution to companies that bought property and casualty insurance through Aon, and end the practice of soliciting incentive fees.

The agreement was similar to one announced in January with Marsh & McLennan Companies Inc., the nation's largest broker. Marsh & McLennan agreed to pay $850 million in restitution.

In the Marsh case, top executives were ousted and several faced criminal charges. That did not happen with Aon.

Citing those differences, state GOP Chairman Stephen Minarik said Thursday that Spitzer should give back the donation, first reported Thursday in the New York Post.

"Not only should Eliot Spitzer give this money back, Spitzer should explain to all New Yorkers what he knew, and when he knew it," Minarik said. "This story raised serious questions."

Spitzer spokesman Darren Dopp said there were no plans to return the donation and he disputed a contention in the Post story that the Aon settlement was a "slap on the wrist." Dopp said that proportionately, Aon wound up paying more in restitution that Marsh.

"That's a little more than a slap on the wrist," agreed J. Robert Hunter, director of insurance for the Consumer Federation of America.

Aon spokesman Orendorff also said the settlement was more than a slap, and disputed a claim in the Post report that Ferrucci, after leaving the company in 2003, had continued as a consultant to Aon.

Spitzer has said he does not accept campaign donations from companies under investigation by his office or from their executives.

Republican Gov. George Pataki (search) has not said if he will seek a fourth term next year.