Undercover investigators posing as students interested in enrolling at 15 for-profit colleges found that recruiters at four of the colleges encouraged prospective students to lie on their financial aid applications  and all 15 misled potential students about their programs’ cost, quality and duration, or the average salary of graduates, according to a federal report.

The report and its accompanying video are to be released publicly Wednesday by the Government Accountability Office, the auditing arm of Congress, at an oversight hearing on for-profit colleges by the Senate Committee on Health, Education Labor and Pensions.

The report does not identify the colleges involved, but it includes both privately held and publicly traded institutions in Arizona, California, Florida, Illinois, Pennsylvania, Texas and Washington, D.C. According to the report, the colleges in question were chosen because they got nearly 90 percent of their revenues from federal aid, or they were in states that are among the top 10 recipients of Title IV money.

The fast-growing for-profit education industry, which received more than $4 billion in federal grants and $20 billion in Department of Education loans last year, has become a source of concern, with many lawmakers suggesting that too much taxpayer money is being used to generate profits for the colleges, instead of providing students with a useful high-quality education.