Anthrax in Mail Was Newly Made, Investigators Say
Scientists have determined that the anthrax powder sent through the mail last fall was fresh, made no more than two years before it was sent, senior government officials said. The new finding has concerned investigators, who say it indicates that whoever sent the anthrax could make more and strike again.

Establishing the age of the anthrax that killed five people has strengthened the theory that the person behind the mailings has a direct and current connection to a microbiology laboratory and may have used relatively new equipment. "We're still looking for someone who fits the criteria of training, knowledge, education, experience and skill," a government official said.

The new finding casts serious doubt on another theory that had complicated the so far fruitless investigation: that the culprit had stolen or somehow obtained an old laboratory sample of powdered anthrax, from a strain first identified in 1981.

The dating of the anthrax as recent suggests that the person who mailed it prepared the germs on his own and has the ability to make more without relying on old material, possibly taken from the small supplies of anthrax that the government keeps for testing new kinds of defenses against dangerous microbes.

Officials said the F.B.I. determined that the anthrax was fresh by radiocarbon dating, a standard means of estimating the age of biological samples. It measures how much radioactive carbon a living thing has lost since it died or, in the case of anthrax spores, since they went into suspended animation.

As the case now stands, investigators say they believe that the mailer, if ever caught, will fit the profile offered by F.B.I. behavioral scientists, who theorize that the anthrax killer is a male loner with a scientific bent and a grudge against society, a man who feels comfortable in the Trenton area, where the letters were postmarked. The investigators are uncertain whether the perpetrator is American or foreign.

The new forensic evidence about the anthrax, a germ of domestic origin usually referred to as the Ames strain, has been closely held among investigators. Laboratory experts and senior investigators will meet this coming week with the F.B.I. director, Robert S. Mueller III, to discuss the evidence in the case. Among the topics will be the results of months of sophisticated studies conducted on the anthrax contained in the letter sent on Oct. 9, 2001, to Senator Patrick J. Leahy, Democrat of Vermont.

Even though they are making progress in the science of anthrax, officials acknowledge that they have no prime suspect and have not narrowed the list of possible subjects, which in fact appears to be expanding. Investigators have a list of about 50 people, which is updated periodically as possible subjects are added or deleted.
http://www.nytimes.com/2002/06/23/national/23ANTH.html?pagewanted=all&position=top