, 65, of Silver Spring, Md., pleaded guilty Thursday to a misdemeanor campaign finance violation.
Later, a consultant for the same district-based accounting firm was charged with a similar offense.
Calhoun works for Bazilio Cobb Associates, a company previously owned by Jeffrey Thompson.
is part of a network of more than 100 donors linked in some way to Thompson who have given hundreds of thousands of dollars to political candidates.
The case against Calhoun
signals a new turn in U.S. Attorney Ronald Machenâ€™s long-running investigation of corruption in district politics, and Calhounâ€™s lawyer said after the hearing that he
expects many more people to be brought in on similar charges.
The charges against Calhoun
and Straughter are the first related to Thompsonâ€™s fundraising for candidates outside the district, where many local elected officials have benefited from his largesse.
Calhoun pleaded guilty Thursday to a single count of making straw contributions in 2011 to Delegate Donna Christensen, a Democrat who represents the U.S. Virgin Islands in Congress.
Records show that Calhoun
and his wife contributed the same amounts on the same dates to Specter and Norton, although their donations to Specter were returned.
was reimbursed by Thompson for $83,400 in federal contributions and $76,600 in contributions to local officials in the district, court papers show.
told the judge that he
would write a personal check to candidates, and usually the next day, he
would receive a check from his
employer labeled as an advance on a bonus.