WASHINGTON -- Blind trusts are designed to keep an arm's-length distance between federal officials and their investments, to avoid conflicts of interest. But documents show that Senate Majority Leader Bill Frist knew quite a bit about his accounts from nearly two dozen letters from the trust administrators.

Frist, R-Tenn., received regular updates of transfers of assets to his blind trusts and sales of assets. He also was able to initiate a stock sale of a hospital chain founded by his family with perfect timing. Shortly after the sale this summer, the stock price dived.

A possible presidential contender in 2008, Frist now faces dual investigations by the U.S. attorney for the Southern District of New York and the Securities and Exchange Commission into his stock sales.

The stock was in HCA Inc., a chain of hospitals founded in the late 1960s by Frist's father and brother. At the time of the sale, insiders also were selling. Shortly after that sale, the stock price dipped because of a warning that earnings would not meet Wall Street expectations.

Whether Frist knew too much about his investments, or took advantage of insider trading, is not known. But the potential political damage increased in recent days.

Documents on file with the Senate show the trustees for Frist and his immediate family wrote the senator nearly two dozen times between 2001 and July 2005.

The documents list assets going into the account and assets sold. Some assets have a dollar range of the investment's value and some list the number of shares.

Frist's 2005 financial disclosure form lists blind trusts valued between $7 million and $35 million.

Asked in a television interview in January 2003 whether he should sell his HCA stock, Frist responded, "Well, I think really for our viewers it should be understood that I put this into a blind trust. So as far as I know, I own no HCA stock"