FBI Uses DNA Analysis to Pinpoint Ricin Source

Using DNA analysis, federal authorities are trying to glean clues about the source of ricin found in a Senate mailroom and in two earlier letter mailings, including where castor plants used to make the poisons were grown.

Lee Browning, a researcher with a Texas seed company who has consulted with the FBI about ricin production, said a DNA analysis will show “if it’s coming from South Carolina, Georgia, Florida or Texas.”

Authorities have not found the source of ricin discovered in the office of Senate Majority Leader Bill Frist (R-Tenn.), or of samples found last year in postal facilities serving the White House.