WASHINGTON (Reuters) - A Pentagon spy agency said tests on a letter sent to a U.S. military base has found "possible biological toxins," which the top Democrat in the Senate identified as the highly lethal poison ricin - the same substance sent in the mail to President Barack Obama last week.
The United States is on edge following the Boston Marathon bombings and the discovery of letters laced with ricin addressed to Obama and Republican U.S. Senator Roger Wicker of Mississippi.
The Mississippi man charged with sending the toxic letters was released from jail on bond on Tuesday, the U.S. Marshals Service said.
The latest letter was detected among incoming mail by Defense Intelligence Agency security personnel on Tuesday morning at Joint Base Anacostia-Bolling in Washington, D.C., a DIA spokesman said. A spokesman for the base confirmed an ongoing "hazardous material incident."
"Tests by experts called in to assist indicate possible biological toxins," the DIA spokesman said.
Senate Majority Leader Harry Reid, asked about the release of the Mississippi man charged in last week's ricin letters to Obama and Wicker, said the Bolling incident involved the "same substance."
The DIA declined further comment until its investigation was complete.
(Reporting by Phil Stewart and David Lawder; Editing by Eric Beech)