Federal investigators have raised concerns about an advocacy group’s “Census of Senior Citizens,” a mass mailing that seeks opinions and donations from elderly Americans, reports The Kansas City Star.

The Kansas City, Mo., office of the Federal Bureau of Investigation issued a public warning about the mailing, which queries recipients on Social Security, immigration, health care, and other issues and seeks a $6 donation for the Council on Seniors, a program of the Civic Council, in Frederick, Md.

Don Reimal, mayor of nearby Independence, Mo., said he feared people would confuse the Council on Seniors questionnaire with official U.S. Census Bureau mailings and thus not fill out the federal government’s census forms when they are sent out later this year. Thomas Cromwell, president of the Civic Council, said any such confusion is unintentional.