U.S. Capitol Police are looking into threatening statements made against Senate Majority Leader Harry Reid.
A police spokesman declined to give further details Monday, citing an ongoing investigation.
Reid, D-Nev., has been an outspoken critic of Cliven Bundy, a Nevada rancher who has thwarted U.S. government efforts to seize his family's cattle over his failure to pay more than $1 million in grazing fees and penalties for use of government land over the past 20 years.
The Bureau of Land Management was forced to call off a roundup of Bundy's cattle on April 12 after hundreds of Bundy supporters, including some armed with handguns and rifles, protested. Reid called them "domestic terrorists" and said Bundy was a "hateful racist" after the rancher suggested that African-Americans might have had it better as slaves picking cotton. Reid has called on Republican leaders to denounce what he called Bundy's "hateful, dangerous extremism."
A spokesman for Reid declined to comment Monday.