Letters that sparked anthrax crisis

The FBI is stepping up America's desperate attempts to trace more anthrax-laced letters, amid fears that many more have been sent than was at first thought.

As the deaths of two postal workers and the serious illness of a third were attributed to the disease, the FBI today released copies of letters already posted to prominent figures in the hope that someone might recognise the handwriting.

With the crisis apparently spiralling out of control, anthrax spores were found in a post room serving the White House, and President Bush was forced to reassure the country that he does not have the disease. White House staff, including the Vice President Dick Cheney, were issued with anti-anthrax drugs within days of the terrorist attacks of 11 September.

The letters released by the FBI are all dated 11 September and all were postmarked from Trenton, New Jersey. Letters sent to NBC TV news anchor Tom Brokaw and the New York

Post appeared identical. Both warned recipients to "Take penacilin now," - with the same misspelling - and the chilling taunt "Death to America", "Death to Israel" and "Allah is Great". The letter sent to Senate majority leader Tom Daschle was more direct. It said: "You can not stop us. We have this anthrax. You die now. Are you afraid? Death to America. Death to Israel. Allah is great." The letter contained seven lines written in block letters.

Some experts in criminal profiling believe the release of the letters and the identical dates are indications that investigators believe they are dealing with a domestic terrorists. They point out that authorities caught Theodore Kaczynski, the socalled Unabomber, after releasing copies of his 35,000-word "manifesto", which was recognised by his brother.

Nevertheless, the thinking within the White House remains that the anthrax attacks are being coordinated by Osama bin Laden's al Qaeda terrorist network. Press secretary Ari Fleischer said: "That has been the operating suspicion of the White House for a considerable period of time."

Minority leader Dick Gephardt said he also holds Bin Laden's network responsible. "I don't think there's a way to prove that but I think we all suspect that," he said. Investigatorsare still trying to find the source of anthrax spores discovered on a letter-opening machine at an office used to process mail for the White House. Mr Bush's office said only a "small concentration" of anthrax had been found in the building, which is several miles from the President's residence.

The amount found - less than 500 spores - is well below the 8,000 that would cause the deadlier inhaled version of the disease. The possibility that the perpetrators are postal workers or individuals who had access to postal facilities is being considered. The FBI now knows that one person suspected of suffering from inhalation anthrax in the Washington area had a connection to a postal sorting office but is not a postal worker.

Three people have now suffered anthrax-related deaths, including the British journalist Bob Stevens, who was infected by a letter sent to his employers, the National Enquirer.

In addition to the two postal workers who have died, two more in Washington are in hospital with inhalation anthrax and four other cases are being treated as suspicious.

Another 12 cases are being monitored as "low suspicion".