The main investigation concerned a company that was suspected of illegally manipulating currency markets.

"We must not allow pharmaceutical companies to abuse American consumers, and place lives at risk, by illegally manipulating supply," the letter concludes.

Early in 2012, Park was accused of illegally manipulating the army draft health checkup to have his son sent to a favorable post.

"We have always said if anyone is illegally manipulating markets they should be held accountable," Ms. Buchan said.

To be sure, some people have accused Mr. Vinik of illegally manipulating stock prices as part of his trading activities.

One Justice task force was investigating whether Philip Morris had illegally manipulated the level of nicotine in cigarettes to keep smokers addicted.

The Justice Department is investigating allegations that bidders for cellular telephone licenses may have illegally manipulated recent wireless spectrum auctions, officials said today.

Saunders was then asked to resign following revelations that the Guinness stock price had probably been illegally manipulated (see Guinness share-trading fraud).

The Securities and Futures Commission of Hong Kong said today that it was investigating whether markets were illegally manipulated on Friday.

Last year, TAP Pharmaceutical Products paid $875 million to settle criminal and civil charges that it had illegally manipulated the Medicare and Medicaid programs.