A white powder found in the office of Senate Majority Leader Bill Frist, R-TN, tested positive as ricin, a deadly poison, Frist said Feb. 3.

“Somebody in all likelihood manufactured this with intent to harm,” he said as the Senate prepared to open debate on a $317 billion highway bill. “This is a criminal investigation.”

Several members of Frist's staff went through decontamination procedures, but there were no reports of anyone becoming sick. Capitol Police advised lawmakers not to open any mail.

One reason that all three Senate office buildings were closed was to give authorities an opportunity to check senators' mail, The Associated Press reported.

Meanwhile, Connecticut and federal authorities said they are investigating a suspicious letter laced with white powder discovered at a postal facility Feb. 3 in Wallingford. The letter was addressed to the Republican National Committee, according to press accounts.

SC investigation continues

Investigators in South Carolina have sent out thousands of fliers to residents looking for clues to who is responsible for ricin found at a post office in Greenville in October.

In the letter containing the substance, which was addressed to the U.S. Department of Transportation, the writer threatened to "start dumping" ricin if new federal trucking regulations requiring drivers to rest longer weren't repealed.

No connection between that incident and the one in Sen. Frist’s office has been found thus far, according to press reports.

A reward of up to $100,000 is being offered for information leading to the arrest and conviction of the individual(s) responsible for introducing the threatening letter addressed to DOT containing ricin.

The author claimed to be a fleet owner of a tanker company and demanded that the present laws regarding hours-of-service regulations remain unchanged. Typewritten on the exterior of the envelope was the following warning:

CAUTION RICIN POISON

Enclosed in sealed container

Do not open without proper protection

The following is a representation of the language contained in the threat letter:

to the department of transportation: I?m a fleet owner of a tanker company.

I have easy access to castor pulp. If my demand is dismissed I?m capable of making Ricin.

My demand is simple, January 4 2004 starts the new hours of service for trucks which include a ridiculous ten hours in the sleeper berth. Keep at eight or I will start dumping.

You have been warned this is the only letter that will be sent by me.

Fallen Angel

If anyone has information, call the Tip Line 1-866-839-6241.