Aon Corp. (AOC), the world's second-largest insurance brokerage, will probably be the next to face a lawsuit from Eliot Spitzer (search), an official in his office said, as the New York Attorney General's investigation into the insurance industry intensifies.

Any charges against Aon would follow Spitzer's civil suit against Marsh & McLennan Cos. Inc. (MMC) Oct. 14, which accused the world's No. 1 insurance brokerage of cheating its customers with bogus bids, price fixing and steering insurance coverage insurers paying the highest fees to Marsh.

"We are taking a very close look at Aon and its business practices," the Attorney General's office told Reuters Tuesday. "They are a top focus. They're are on a short list."

Aon representatives did not return a call for comment Tuesday.

The Marsh suit was the first action to arise from six months of examining documents from insurance companies and brokers. Spitzer has warned that his probe will extend to many companies and across all types of insurance.

After apparent evidence of deceptive and coercive practices were discovered at Marsh earlier this year, Spitzer's office moved on to other insurance brokers and many insurance carriers that participated in questionable schemes.

Aon, which together with Marsh controls more than 70 percent of the insurance market, was the logical next step, a person close to the inquiry said.