The FBI is considering draining a spring-fed pond that is up to an acre in size and 10 feet deep in Frederick Municipal Forest, Mayor Jennifer P. Dougherty said Sunday. "The possibility of draining one of the fire ponds in our watershed does exist," she said.
The plan stems from a new FBI theory reported Sunday by The Washington Post that the person behind the attacks could have packed the deadly spores into envelopes under water without being infected or leaving traces on open land.
The theory is based on evidence recovered from the pond this past winter, the Post reported Sunday, citing anonymous sources close to the investigation.
The FBI declined to comment on the Post report or on searches conducted at a series of ponds in the forest.
The attacks nearly 19 months ago killed five people and sickened 13 others. The pond findings offer physical evidence in a case that so far has been built almost exclusively on circumstantial clues, the Post quoted sources as saying.
Two sources familiar with the items recovered from one of the ponds described a clear box, with holes that could accommodate gloves to protect the user during work, the Post reported. So-called glove boxes are commonly used to handle dangerous pathogens. Also recovered were vials wrapped in plastic.
For protection against airborne bacteria, a person could put envelopes and secured anthrax powder into the box, then wade into shallow water and submerge it to put the bacteria inside the envelopes, some involved in the case believe, the Post said. Afterward, the envelopes could have been sealed in plastic bags before being removed from the underwater chamber.
Other sources told the newspaper the work could have been done on land and the materials discarded in the pond.
The FBI has said nothing publicly about the material divers recovered during the December and January search missions.
Sources close to the case told the Post that the discovery in the ponds was so compelling that the FBI now plans to drain one of the ponds of thousands of gallons of water for a detailed search this summer.
Heather Lynch, a spokeswoman for the Maryland Department of Natural Resources, declined to comment on that plan Sunday.
Dougherty said Sunday that draining the pond was "one of the possibilities."
"Obviously, they want to find other evidence, and they think that, as I recall, they want to find other things being hidden by the muck," she said.
"Mostly people like to know that when they turn on the water in the morning and open the faucet, it's safe," Dougherty told CBS Radio News. "I have been assured and we will continue to test our water as the FBI did to make sure we don't have a risk because of this investigation."
The search of the ponds was based on a tip, the Post reported.
Some investigators said the water theory is the result of the FBI's interest in Steven Hatfill, a physician and bioterrorism expert who formerly worked as a researcher at the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick in Frederick. That facility is the primary custodian of the strain of anthrax found in the envelopes sent to the victims.
Attorney General John Ashcroft has described Hatfill as "a person of interest" in the investigation. Hatfill formerly lived in an apartment outside Fort Detrick's main gate, about eight miles from the ponds.
Hatfill's attorney, Thomas Connolly, called the water theory "far-fetched." He said Hatfill had nothing to do with the anthrax crimes.
Connolly said the equipment found in earlier searches of the pond could have been used in a Methamphetamine lab.
"We haven't had such a problem in our community," said Dougherty. "Every community deals with drug and drug-related problems, but this was a surprise to me."