OMAHA, Neb. (AP) ? A subsidiary of billionaire investor Warren Buffett's Berkshire Hathaway Inc. has been subpoenaed in the investigation of a former professional liability insurer based in Virginia and its Bermuda-based affiliate.

In a filing on Tuesday with the Securities and Exchange Commission, Berkshire said General Reinsurance Corp. was subpoenaed for documents in October, 2003 by a US attorney's office in Virginia in an investigation of Reciprocal of America, a former liability insurer of doctors, hospitals and lawyers.

Four current and former employees of General Reinsurance, including a former president, were included in the subpoenas, Berkshire said.

Citing anonymous sources familiar with the Reciprocal of America probe, the Wall Street Journal reported on Wednesday that federal prosecutors were investigating whether General Reinsurance played a lead role in helping the company, which collapsed in 2003, disguise loans as reinsurance.

Berkshire said the US Attorney and Department of Justice in December "and on several occasions since then" sought information about Reciprocal and a related Bermuda reinsurer, First Virginia Reinsurance Ltd. The requests also sought information about General Re's dealings with "other insurers."

In 2003, the Bermuda liquidators of First Virginia Re filed a claim in the US courts for upwards of $57 million to be returned from Reciprocal.

The Bermuda insurance company was ordered to be wound up in October, 2003.

The company, which has shortfalls of between $79 million and $111 million, was set up in the 1980s as a reinsurance vehicle for Reciprocal of America.

Berkshire's chief financial officer, Marc Hamburg, did not immediately return a telephone call from the Associated Press on Wednesday seeking comment. Officials with General Reinsurance also didn't immediately return a phone message.

Buffett is chairman of Omaha-based Berkshire, which acquired General Re Corp. in 1998.

General Reinsurance, a subsidiary of General Re Corp., provided various reinsurance coverages to Reciprocal of America from the late 1970s through 2002. Insurers buy reinsurance to spread out their own risk.

Reciprocal of America was placed in receivership in January 2003 with unpaid liabilities of $450 million.

Last month, two of its top executives pleaded guilty to conspiracy to commit insurance fraud and other charges related to the company's collapse.

In December 2004 and several times since, General Reinsurance has received requests for additional information concerning Reciprocal of America from the US attorney's office and the Justice Department, Hamburg said in the filing.

General Reinsurance has been cooperating with the probe and cannot predict whether its outcome will hurt its financial statements, Hamburg said.

Berkshire's Class A stock fell $500, or 0.6 percent, to close at $90,300 on Wednesday on the New York Stock Exchange.

Federal and state regulators around the country have been examining whether insurance companies have sold products that may not really be insurance, but instead may be aimed at helping companies smooth out earnings.

In December, General Re Corp. received subpoenas from the New York state attorney general's office and a request for information from the Securities and Exchange Commission on its reinsurance business. Berkshire said it and General Re were cooperating with those requests.

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