Investigations into fraud at for-profit colleges conducted by a special unit of the Education Department have routinely been derailed under Education Secretary Betsy DeVos, The New York Times reports. Current and former employees of the unit told the Times many of the shelved investigations concerned for-profit colleges where DeVos’ top hires had previously worked. DeVry Education Group, Bridgepoint Education, and Career Operation Corporation, all of which run major for-profit colleges, were under scrutiny by investigators in late 2016 until the investigations mysteriously went dark—and former employees of those institutions began working for DeVos, according to the Times. While the unit was made up of about 12 lawyers and investigators under Obama, it now consists of only three. Several Democratic lawmakers have expressed concerns over the trend. “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,” Sen. Elizabeth Warren (D-MA) was quoted as saying by the Times.