Officials are investigating 10 more letters with a suspicious white power found Friday in District schools and mail facilities.
Emergency crews have responded to six schools, according to D.C. Police Chief Cathy Lanier. Another four letters were intercepted by postal inspectors before reaching the schools they were intended for, Pat Collins reported.
“We expected this,” Lanier said. “We figured probably through the day today and maybe Monday, working on trying to recover the remainder of the letters.”
Some of the schools involved Friday include: Prospect Learning Center in Northeast, Bancroft Elementary School and Dunbar High School in Northwest and Drew Elementary School in Northeast.
Nothing suspicious was found at Dunbar High, officials said.
FBI spokesman Lindsay Godwin told the Associated Press that letters were collected at a mail facility Friday morning by U.S. postal inspectors. She did not know which schools those
letters were addressed to.
The discoveries came a day after 29 suspicious letters were found at D.C. public schools on Thursday.
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Investigators said that the letters found Thursday were identical to white-powder letters received by District schools in October 2010, and they believe the letters contain a harmless white powder.
DC Fire/EMS spokesman Pete Piringer confirmed that according to the FBI, there had been 29 school hazmat incidents Thursday.
The letters are similar enough to each other to believe that they were sent by the same source.
“We respond to a lot of white-powder letters,” Assistant Director in Charge of the Washington Field Office of the FBI James W. McJunkin said. “This is just unique because it looks like it’s coming from the same source or sources.”
The FBI does not consider the letters a prank or a joke but a "serious criminal offense," McJunkin said.
Former homicide detective Dwayne Stanton warned that while the letters could be a prank, they could also be a trial run, which is why citizens and authorities alike must remain vigilant.
“It also could be operatives working, and when operatives do these type of things, what they’re doing is they run tests to see how long it takes the establishment to respond and fix a situation, and this could very well be a test as well,” Stanton said.
Sources said that each envelope has a sheet of paper in it with "AL-AQEDA-FBI" typed on the paper. The letters also include white powder.
So far, none of the letters has been found to contain hazardous substances, but the FBI is treating each letter found like it could be dangerous. Anyone who receives such a letter should report it to police or the fire department.
Each of the letters is addressed with a type-written sticker on the envelope. All of the letters have Dallas, Texas, postmarks on them.
Stay with NBCWashington.com for more information.
