Among the Americans referred to trial is Sam LaHood, the Egypt chief for the International Republican Institute and the son of Ray LaHood, the United States secretary of transportation and a former Republican congressman from Illinois.

The International Republican Institute and its sister organization, the National Democratic Institute, are independent nonprofits with close ties to the Congressional leadership that promote democracy in countries around the world.

The two groups are the highest-profile targets of the investigation, which has been accompanied by a drumbeat of anti-American rhetoric from the Egypt’s military-led government suggesting that Washington has been paying to stir unrest in the Egyptian streets.