There was no indication it was an attack aimed at people, said Alan Etter, District of Columbia fire and EMS spokesman. No injuries were reported.
However, members of the FBI's joint terrorism task force joined the investigation. "They are observing it; they are gathering information," Etter said.
The Greenbelt station on the Green Line in suburban Maryland and the Takoma Park station on the Red Line in the city were closed, said Cathy Asato, a spokeswoman for Washington Metropolitan Area Transit Authority. The agency's Web site later said the Rhode Island station in Washington also was closed.
Twenty dead birds were found outside the Greenbelt station, 15 at the Branch Avenue station and a few at other stations, Etter said.
Investigators determined the substance at the Greenbelt station was d-Con rat poison, Etter said. "We suspect very strongly that it's the same chemical at the other stations," he said.
Investigators were looking for a person in a black pickup truck who witnesses saw spraying the material, he said.
"Metro will have to figure out if this person works for them or is a contractor or what," Etter said.
"We don't know how many dead birds are going to be connected to this," he said. "The message to the public is if you see a dead bird, don't touch it, and contact the authorities."
Güncelleme Tarihi: 29 Temmuz 2007, 23:53