Elizabeth Hill, a spokeswoman for the Education Department, attributed the reduction of the group to attrition and said that “conducting investigations is but one way the investigations team contributes to the department’s broad effort to provide oversight.” She said that none of the new employees who had previously worked in the for-profit education industry had influenced the unit’s work.

She also said the team’s deployment on student loan forgiveness applications was an “operational decision” that “neither points to a curtailment of our school oversight efforts nor indicates a conscious effort to ignore ‘large-scale’ investigations.”

Aaron Ament, a former chief of staff to the office of the department’s general counsel who helped create the team under President Barack Obama, said it had been intended to protect students from fraudulent for-profit colleges. “Unfortunately, Secretary DeVos seems to think the colleges need protection from their students,” said Mr. Ament, who is now president of the National Student Legal Defense Network.

Senator Elizabeth Warren, a Democrat from Massachusetts, also criticized the team’s new direction. Ms. DeVos has taken a number of actions to roll back or delay regulations that sought to rein in abuses and predatory practices among for-profit colleges — actions that Ms. Warren and other Democrats have said put the industry’s interests ahead of those of students.

Image Ms. DeVos appointed Julian Schmoke, a former dean at DeVry, to supervise the investigative team.

“Secretary DeVos has filled the department with for-profit college hacks who only care about making sham schools rich and shutting down investigations into fraud,” Ms. Warren said.

DeVry did not respond to requests for comment, and Mr. Schmoke declined to be interviewed. Mr. Schmoke recused himself from matters involving DeVry, according to the department.