Washington Metropolitan Police officials said Norquist, president of Americans for Tax Reform, received the bomb threat by telephone and contacted police, The Hill reported.
"The police are conducting an investigation" into the matter, John Kartch, director of communications for Americans for Tax Reform, said in an e-mail to The Hill.
Norquist obtained the signatures of all but 13 Republican congressional members on his Taxpayer Protection Pledge, a commitment to oppose efforts to create a net increase in federal taxes.
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